In juinor high, I went through a period that lasted several months where I would get sick to my stomach every time I ate. It wasn't gas or anything like that. I went to the doctor who recommended all sorts of things that didn't work. It finally just went away one day. I know yours doesn't happen because of eating, but I think mine was also some sort of stress thing. Take a chill pill and see if that helps

But seriously, I bet it is stress. You should try to make yourself eat a regular, healthy diet and do some relaxing things. I'm a very stressed out person and its hard to take care of yourself when you're stressed. But it will make you feel better to sleep and eat regularly and try to not let your stress consume you.

I do something really stupid to try to forget my worries and troubles. I picture a dry erase board in my mind and I write down everything I'm worrying about. Then I picture a giant eraser erasing it all. Every time a thought pops into my head about one of those things, I picture erasing it again. Its stupid but it really helps me clear my mind.