I'm 36, never been pregnant before. I was at 5 weeks. Had 5 positive tests from 3 different brands. Missed period and today marked 8 days late. Unfortunately, I started phentermine a few weeks ago. I stopped last week. Had symptoms such as sore beasts for past 3 weeks, back ache, mild headaches and cramps but unlike period cramps, I've been tired and the past 2 days urinating more often. This morning I woke up to bleeding. Went to the ER only to be told I was not pregnant and got diagnosed with "abnormal vaginal bleeding". The doctor knew nothing about phentermine and said it wouldn't hurt anything. I found a lot online saying it was found to cause miscarriage in lab rats. Every other doctor I've talked to said not to even take it when trying to get pregnant. Anyway, I've had worse cramping and back ache all day. The blood is bright, but not heavy. This "abnormal bleeding" is nothing like my normal periods. The cramps and back ache are never this bad and I never have clots. I passed a nickel size piece this afternoon. I have to follow up with my OB in a week. Fingers crossed we can try again soon and everything is ok. Sorry for the long post. It's been a rough day :(