CRYING OUT FOR HELP!!! =[ Whats wronge with my body since this miscarriage?

I had a miscarriage febuary7 the doctors guessed i was maybe 4 weeks to 6 weeks pregnant. The same day as my miscarriage my hcg level was already down to 4. A few weeks later it was still at 4.All pregnancy tests come back negative. I did not have a dnc. They did an ultrasound on me the day after and said there was nothing inside me and i am not having an ectopic pregnancy. I only new i was pregnant for 1 day and now im tinking maybe i wasnt even really pregnant maybe that one home pregnancy test i took was negative and my period was just 3 days late. but even so what is happening now if im not pregnant..?