Miscarriage?

About a month ago I had unprotected sex.. I also started birth control that same day.. and the next day took the morning after pill ... days later my hormones were driving me crazy... ppl convinced me its just the effects of the pills and the B.C.. but I'm my heart I just felt I was pregnant. Took two tests both say I'm not... but in my heart I just felt that a baby was in my womb... plus no period since then. Went on vacation and lifted heavy bags... and started having back pain and spotting ... my mom says she thinks I'm having a miscarriage.... and I think she's correct. Am I crazy???!!