Period problems... Please help (almost 19 years old)?

Okay so my period has been irregular for about 4 months now. The first 2 months it started a day then stopped a day and repeated and the 3rd month is was heavy and lasted for about 4 days( I used tampons and didn't have a problem) I'm on my period now and i started out using a pad bc i didn't know how my period was going to be this time, it got a little heavy and I was uncomfortable sitting in my blood lol, so I put in a tampon. I left it in for a couple hours and took it out and there was barley any blood and my period had stopped, I left the tampon out and put a pad back on. I took a nap and when I woke up I was bleeding heavy again so I put in another tampon and the same thing happened again! My blood is coming out in clots in the toilet when I wear a pad some are clumps in the toilet and others are the stringy kind the hang out of you! I started to go to gyn Friday and she said everything seems normal and she doesn't understand what is happening with my period! I'm so confused :(