Kind of concerned

Okay. I know some symptoms during your period are normal, especially if they happen every month but mine seem to be getting progressively worse. I'm 16 now but when I was 14 the most it would be is bloating. Now I usually have a heat flash, really bad cramps, dizziness, bloating, and diarrhea AT THE SAME TIME. I used to write it off as just my period but lately it's been different. One time I got these symptoms while I was over seas, but my period wasn't even close to starting. When the symptoms passed, my period came two weeks later on time. Some one suggested I'm dehydrated but I'm not sure. During my most recent period, I had some of these symptoms and my vision blacked out in the middle of tennis practice. Once I recovered I had diarrhea for a good 15 minutes. Any idea what's going on??