I don't have a solution, but I do understand what you are talking about. years ago, when I was in my early 20s I had the same uncomfortable feeling eating in public. My stomach would just go into knots! If I went out with someone they would compain that I was being rude by not eating when others were eating. I just could not explain to them why I felt the way I felt.
I did get over it eventually. Now I wish I felt that way again occasionally as I could lose a few pounds and that would help!