Feeling Off?

Okay so I haven't had unprotected sex, at all, ever. I also haven't had sex since before my period last month (April). However, for the last two days, if been feeling super nauseous. Nothing I eat sits well with my stomach. I'm thinking it might be a mixture of stress (finals week), and lately I haven't been eating as good as I was before (lots of fast, unhealthy food compared to salads and fruits that I've been eating all semester). I was just wondering if anyone has some insight or some home remedies to help? I've tried taking Tums, and they didn't help much. I've tried a heating pad to ease the feeling, but that didn't help either.