VERY heavy bleeding

Alright.. I am 15 and I am on the pill but I dont take it every day, usually about every 2nd day or so. About a week ago, I was spotting for about a day and i was feeling sick and stuff so i got worried and i took a pregnancy test. One thing is that i dont think i peed enough on the test and the second thing is that it said it could only detect pregnany up to the first missed period but i took it before i missed a period and the results were negative. So i waited and my period came normally. Then, about a week and a half later, i hadnt taken 2 of my birth control pills and i started my period (2 weeks earlier than it was supposed to start). Except it was unusuall because it was very very light for the first approx. 3 days. But then all of a sudden, on the 4th or 5th day it was soooooo heavy. I had a super plus tampon in and i "went over" in 10 minutes. I went through 5 super plus tampons in less than an hour. It is sooo heavy. So I dont know what to think about this. Im confused why it started so early and its so irregular. Oh and this is the first time in my life that i ever had an irregular period. They are always the same. But this one is early, was very light and then very very very heavy. Im confused and i dont know what to think or do about it. Im still getting dizzy and sick and stuff too. My friend suggested that maybe i was pregnant and had a miscarrige. I am so confused. Please help and reply back!