Miscarriage or late period??? HELP

[Mykaelac]

I'm 18 and me and my boyfriend are sexually active. Last month my period was a week late but it was normal. I had cramping throughout this past month. I usually get my period the 16 and it's always over by the 22. It never last more than a few days. I've been nauseous  I started spotting light pink white mucus on the 3rd of this month (May) it lasted for the day and then I had brown colored bleeding. The next morning I started bleeding really heavy and had clotting. Now I have really bad cramps and sharp quick pains in my ovaries. When I go to change my tampon it hurts even worse. the bleeding is off and on. I was bleeding through a tampon every hour and then it gets light and then heavy again.

[BOO_2012]

You should go to the emergency room

[Mykaelac]

I went to the doctor a few weeks ago and they did a pregnancy test because they thought I was pregnant but it came out negative. Could this be an early miscarriage? I don't think I was/am pregant but I just don't know I'm really confused.