How to cope with your baby having to stay in the hospital and him having so many problems!?

My 3 month old has only been in the hospital since Monday morning but it seems like its been an eternity! Things are really hard right now because I also have a 2.5 yr old and he is not allowed to go to the hospital because its flu season and hes under he age of 12. So now I have to juggle spending time with my children. And I'm already getting stressed because my 3 month old has tremors and they havent figures out why, he has an enlarged heart, he is having to see a speach therapist because he has a hard time taking a bottle, he has to see an eye doctor, he hasnt reached milestones he should have already, they are having to do genetic and chromosome tests, they have done a CT scan, MRI, Xray and ultrasound on his stomach. They still have to give him an echo because the EKG was irregular and he is always congested and his cry sounds horse so they are sending a camera down his throat. and I'm sure I'm forgetting stuff! I am glad they are doing all these tests to find out whats wrong but at the same I'm just ready to have him home with us. I don't know what to do I feel like I'm going crazy from trying to keep myself together because I feel like I'm just gonna fall apart. What can I do when I have no control over this situation?? My mind is racing so I'm sorry if none of this makes any sense I'm just so scared and confused right now