I am a 23 year old healthy female and I am not sure whether I am pregnant or not. I did a pregnancy test on the 13th October and it was positive, with 2 or 3 weeks gone now, and yesterday I experienced some mild cramps and periods. Today I went to the hospital and they did urine pregnancy test and it was negative. I don’t feel any pain but my periods have some small clots. I don’t know what the reasons could be and if there is any possibility that I am not pregnant.