At 3 months, eating mac and cheese shouldn't be challenging your wrap unless the macaroni isn't cooked enough, or you're not chewing it to a liquid. Chew, chew, chew is the mantra around here, and it's worth taking it seriously.
You can cause discomfort and nausea by challenging your wrap, but it shouldn't involve vomiting that won't quit. Esophageal spasms are very painful, but don't mimic nausea and vomiting, at least from what I've read here on the forum.
It sounds as if you got a bad stomach bug. Retching or vomiting are both very hard on the wrap (BTW, I have been able to actually vomit in three different bouts of stomach illness. I could feel the wrap holding things back, but with enough pressure, it gave way enough to vomit.) . Even vomiting/retching one or two times can set your recovery back and make things very uncomfortable for a few weeks. After what you've been through, I expect you've got lots of swelling and irritation.
It's important to baby your wrap. Liquids and soft foods only, until it gets feeling better. It is totally expected to have pain and swallowing discomfort, and even spasm, after such a trauma.
Hang in there...it'll get better again!