Miscarriage?

Tuesday I started bleeding and since I havent started my period this month I thought that I started my period. But a really strange thing. Tuesday night I had contractions and all day tuesday I was having a lot of cramping. But I thought maybe it was just cuz I started my period early. Then all day yesterday I had cramping but bled very little and then this morning I had a lot of cramping and then all of a sudden a big gush of blood and lost alot of gunk. And since then, the bleeding has stopped. I called my doctor and told her I thought I had a miscarriage so she told me to take a hpt to see if its positive. I took a pg test and it was negative. But from this experience, I could swear That I had a miscarriage. I had a miscarriage back in november and it was the same symtoms (symptoms) almost. I just dont know. I mean if I was pregnant I had no idea. I 've had feelings of being exhausted but I had'nt missed a period. I was expecting my period the 20th of this month. I dont know what to think. I still have cramping but the bleeding has stopped. Can anyone tell me if they have had this kind of experience? I think I should go to my Doc and be checked just to make sure, but she said if the test was negative then there is no reason to be checked.