Nursing while newborn congested/ fast let down ?

FTM (first time mom) here. Just yesterday she started kind of breathing more rapidly and sometimes wheezing. I got a cool mist humidifier to see if it helps and when i used the bulb syringe in her nose it got nothing out. All i saw was a little dried snot in her nose. When i nurse her it seems she has trouble breathing out her nose too. She didn't have a fever. We ended up going to the hospital last night cuz of my nerves😩. It did put me at ease tho. She just was really congested but they said to follow up with pediatrician and watch for her not breathing and turning colors.They gave us some saline drops and said to get that nose frida thing cuz the nasal aspirator can cause trauma cuz her nose so small. Seems like it’s loosening up with the saline drops alone but now when she nurses it’s not for very long. Maybe 5 minutes tops. Then she might spit up a little. I guess because of the congestion. And now I’m noticing that she can only be latched to my left breast maybe 2-3 minutes before unlatching and starting to cough. Is my milk coming to fast? I’ve been trying laidback nursing but two problems i have with that are my extremely large breasts and it still seems as tho it’s too much coming out at once for her. She’s having tons of wet diapers but not many poops. Only one big one and maybe one that was the size of a quarter. Is she constipated ? I’m crying and everything i just want her to be okay. This my baby 😩🤦🏽‍♀️