3 Periods in 1 Month ????

I've had my period 3 times in one month. I had it on june 22 and finished on the 27th and got it again on July 4th and finished on he 10th and just got it again on July 30th. Im cramping really bad and am on heavy. I went to my doctor and he said i was fine. But I don't feel fine this never happened to me and Im really freaking out now. I was at a music video shoot and as they were getting me ready I got really dizzy and almost fainted felt really out of it and then got nauseas and ran to the bathroom to throw up .Im bloated as hell I gained 5 pounds Im hungry all the damn time and super tired and I'm a train wreck over emotional and moody. I don't think I'm pregnant I took 2 HPT and went to the doctors 2 weeks ago and all were negative. Im really scared now. Im scared to go to the doctors at this point now does anyone know what it can possibly be or has had a similar problem??? please help