Hi Joe and welcome to YT! The best advice I can give you is to make sure that you always feed, pet, etc your oldest first. Give him just as much attention at the new puppy. And, mostly, just give it time. I'm not promising they will be best pals but they may be one day. Your oldest is used to being the only dog so it will just take time for him to accept the new one. Hang in there.
Remember, at 8 weeks and 2lbs, your new puppy may need special care that your oldest didn't at 14 weeks. Make sure you read up on the signs of hypoglycemia in dogs, ok? Keep nutrical on hand always. It's good that you are home all day with him
Ask any questions you may have along the way and we'll be here for support