Sometimes it gets worse before it gets better. I used to get sick all the time because of stress and now my immune system made a drammatic turnaround. My current profession is a nurse aide and I breathe in flu, poop particles while wiping old ladies,etc. The winter cold was going around and I felt a little woozy for two days and then I was fine.
I drink coffee too. The one thing I don't do is eat most animal flesh. Sometimes I'll eat fish but I'm cutting that out for a while.
Stress counts for a lot of illness. Try EFT. It works!