lol, well you're not too bad a shape. Pup should be with mom till 12 weeks but it's not like he/she is 6 weeks. I got Jemma at 9 weeks and she is perfectly fine. So I'm not gonna get into that aspect. You're little Chorkie will be fine.
You are going to need to take him out every couple of hours. But I probably would start off with some pee pads myself. I did that with Jemma because I'm not home all day, work, and she has to go somewhere. You can also do the crate training. But it depends on if you are making him a total outside dog. If he will be doing both, pads and outside, I don't think I would do the crate, it isn't necessary.
Try giving a few food nibbles to them both making sure you always give your Marley top priority. This will help in the pack order. Your 1st will see she is top dog and your Chorkie will also see he is NOT top dog.
Taking them together for walks is one of the best things you can do to bond them up. However at 10 weeks, it might be a bit too young yet for that. And the shots situation. This way Marley learns that the little one is staying part of the family. Hold them both but make sure you pick up the Marley first and then the younger one. Hold them together. Give your Marley kisses first. then turn and give the little one kisses. Turn back to Marley and give her a final kiss.
I hope all works out for you. I'm thinking it will. You're the one that needs to get your anxiety under control. Your Marley is going to pick up on it and she will relate it to the new pup. Not good. Think positive. It takes time and needs to be introduced slowly. Make sure you get the little one his own toys too. I'm sure Marley will travel on over to see what the little one has too. But buy something for Marley too and give her it first. It sounds cruel to have the little guy last in everything. But the truth is, there can only be one top dog and that needs to be Marley. If that changes it's because Marley is allowing it. If she didn't, they would be fighting because she isn't going to want to relinquish her crown so to speak, lol. I just want to add that it's not important that you spend more time with Marley, don't put the little one aside cause he needs lots of loving and kisses. Just do things always together but Marley first.
You also may have to feed them with Marley eating first and keeping the little guy away.
You'll do it. It'll be ok. Tell Marly it will be ok too
Cheers!