Y.:
Hello! The first thing that stuck out to me if that your newborn is nursing around the clock. If you are truly nursing every hour, then your new-born is not latching on properly and getting enough milk. He should be able to go at least 2-4 hours between feedings and should only be nursing for 15-20 minutes - any longer than that on each side is pacification and not nursing. Try pumping your milk and giving him a bottle to see how fast he actually drinks it. When nursing, the lower lip and tongue should be extended and the lower jaw should make a long pull-down motion - which is where the sucking comes into effect.
Second - your oldest son needs time to adjust. Having a stomach virus at such a young age is scary. Ensure that his bed doesn't smell anymore - that can make anyone not want to be in the same bed.
While you are nursing your newborn - get your son involved - ask him to hand you things - show you things he can do (run, jump, read, etc.) - do not banish him from the room or tell him to be quiet. The world is not a quiet place and a baby needs to adjust to noise.
When putting your oldest to bed - ensure it's just "his" time. He needs to know he still has a place in the family and it's not just about the baby. Put the baby in a swing or bassinet and give your son one-on-one time - read to him. Our routine is bath, brush (hair and teeth), book and bed - mine are 8 and 6 and LOVE their routine. Assure your son that he is fine and you are there to take care of him too.
Take care.
Cheryl