Ummm...I personally would not let a puppy go that long with out eating. But maybe someone who knows more about this kind of stuff will chime in..

sorry to hear about your pup. I just recently had a problem with vomiting and diarhha. I started the first day with babyfood like gerber chicken look at lables make sure it just chicken and or with vegis like carrots or squash in it only no garlic or onions. I also had some left over gerber rice ceral for babys mixed the 2 together equally. if it seems to thick you can add water to it. I heat this up for 7 sec. in microwave.

When mine had hypoglocymia I had to actually finger feed her she wouldnt eat other wise. Not sure what your pup wgt. but I would start out with small spoonfull,(of the mixture) every 3 hrs, and also give a tsp. at night of pumpkin not the pie filler kind 100% pumkin, you can freeze this too. This will help with the poo for both constipation and diarrha. The next day If no vomiting, take that mixture thats left over make some chicken and rice (white easier on tummy) and take the left over mixture and mix it up and try to see if that helps dont forget the pumpkin at night untill everything comes back to normal for a few days you can also try to add some canned dog food too.

I would also change from science diet this is not good food. try puppy canned from wellness petco sells this in canned. It has good stuff in it. My Ayla loved it and it got her started to eat again. The wellness puppy kibbles are to big though. Both pups love innova for puppie kibbles. you can try the kibbles wet it down some and take chicken and rice mix it all together then start to go hard and start taken back some of the chicken rice slowly to adjust to the new food. But mine still get a small spoonfull on top of there kibbles most of the time lol they are spoiled, but they'll eat the kibble too.
Sorry so long, but its hard to learn what helps bring these pups back to a normal routine most of the vets did not give me any advise on after what to do so learned alot on YT and the hard way and still am as there are not two puppies alike.

I also feel your pain as far as the emotional part, I was in shock for alot of it I too got mine to young, (almost died the 2 night, hypo) had no sleep and was going crazy and everyone around me thought I was crazy too. My best advice get a crate if not already have one put it next to you in your bedroom on the night stand and get some zzzzzzzzz set the alarm for ever 3-4 hrs for pee break maybe a little treat and just to see how he is as to make sure he not having a low specialy if he is not holding down food. Hopefully he takes to a crate. Get some nutracal and if he look or is realy tired, depressed, cant stand up well or gums are grey followed by some protien chicken baby food chicken this levels them out. You can give him this to also get him to eat sometime. I still keep this handy just never know with these guys. Its so hard, when they are sick, we love them so much. I'll pray for you and your little guy to both get well.

Update:

After all of vomiting last night, Magnus slept soundly through the night and in the morning, he was back to his bratty self. He wouldn't eat the boiled rice so I gave him little of his can food and he ate that up right away. As far as I could tell, he didn't seem sick or showed any signs of wanting to throw up. Couple hours later, I tried giving him some rice again and he ate a little of it. Afterwards, I gave him half the dose of the pain med and the stool softner. Decided not to give him the Metronidazole after extensive reading about the med.

Magnus seemed like he's constipated but I'm not sure if the ring in his bum is too small or if he's really constipated. But he did poo. (I wasn't present when he pooped the first time but was told he pooped and seemed to have a bit of a hard time) He tried pooping again before I left for work. He was straining but didn't seem like he was in any pain like last few times I've seen him go. Only about half an inch of poo came out that was hanging out of his bum. -_-; It'll be cleaned off later. I didn't want to wash his bum again and irritate it. Other than that, he seemed energetic and happy.

Kyralayloni:

I will definitely take up on your suggestions and is much appreciated. I think I saw wellness at petsmart as well. I'll pick everything up on my way home tonight. Thanks and please keep praying for Magnus. :)

Our Millie
 

We kept a pup from our second litter that had the same problem. After several trips to the vet we finally got her diet dialed in using about 50%pumpkin. No more straining to go. She is 14 months old now and the problem has gone away now that she has grown up.

Update:

He's gone poo about 3 times today. Straining little less then the previous day and he doesn't seem to be in any pain. Gave him some rice and can food mixed in. He gobbled that up like there no tomorrow. Currently, he's barking up a storm because he wants to play some more.

Over all, I think he's doing really well. At least compared to yesterday. *knock on wood* Thank you for all your prayers/support/advice. I think I would've gotten myself really sick from stress myself if not for the supoort. Please keep praying for him till he's fully recovered.

Update:

I took Magnus to the vet earlier tonight just to have a check up. The vet that usually sees him was there and she took the sutures out. Said just keep giving him the med, apply ointment, keep the collar on for about a week and he should be good.

When we came home, I gave him his dinner which he practically inhaled, gave him the med and pooped not too long after. I didn't see him actually poop but I didn't hear him make any noise. It usually takes him couple times to get something out but it was pretty quick so I don't think he strained at all. PLUS, I didn't see any poo dangling from his bum so I didn't have to put him through cleaning and irritating it.

I'd like to thank everyone for your support and advices. This would've been much harder if I went through it alone. I'll be sure to take some pictures and hopefully, posting them!

Oh what a great relief for You and Magnus:)

Final Update:

Wasn't sure if this was necessary but I wanted to give a official final update. Took Magnus to the vet today for his 2nd set of shots as well as check up on his prolapse. He did GREAT! Vet said his bum looks like nothing ever happened. And he's in good health over all. He didn't even flinch when they took his temp. (Perhaps he's used to getting violated up his bum.... o_O ROFL)

I want to thank everyone for your support. This site and everyone here is a real blessing to many like me. Thanks again.

Sounds good. I hope he continues to do well. He should. He's got a great mommy.:)