I feel very weird lately, someone please give me some advice.?

After my vomiting on the 5 June, I feel very weird until now; my stomach churns a lot, and at times I felt nausea, but don't feel like puking, but I don't have diarrhea or stomach aches. I have been to the doctor who says that it was due to me eating unhealthy food, and I am under some medication which aids in digestion that had made me feel better. But being a student now, I do not feel very comfortable every time I go to school, and I dun seem to like the food served in my canteen. Furthermore, I just feel like staying at home forever, and I suddenly disliked travelling. Why? Is this some phobia or something like that?