Increasing Blackouts?

I'm 15, and I was at a pool with my mother yesterday; Commonly my blackouts are only my vision fading and my eyes hurt, nothing too extreme, but yesterday I felt myself swaying like I was going to fall over..Today when I woke up and got up, I had such an extreme blackout I had to grab onto my dresser and I was keeling over like I was going to fall, it lasted a little longer than they usually do. Then I went to laydown on my couch in my living room, and -again- I got hit with a bad blackout, I know it could be from getting up too fast and such.. but there has to be some medical reason behind it, I've never had a blackout two days in a row.