Heavy periods what do i do?

I just got my first period 5 months ago and ive only had it a few times. The first few times it was really light, and then like 50 days ago i had it last and it was what i think is a normal weight. I got it again yesterday morning and its been extremely heavy and i don't know what to do. My tampon leaks within an hour and a half and there are huge clots and i dont know what to do!!!!