It doesnt matter if he pulls out or not, you can still get pregnant. Go back to doctor and get on birth control after you find out for sure if you were pregnant. Take the pills everyday at the same time. If your stomach gets upset take them before bed. The rubber/latex in condomns are can breakdown if left in a wallet, purse, car, in a hot temperature area, and have expiration dates for a reason. Taking the pills correctly is more effective than just condomns alone, so use both as a better method.
Yes you could have been pregnant and lost the fetus in the first few weeks. The most likely time for a miscarriage is in the first 8wks.
Stop having sex and find out for sure if you were/are pregnant or if it was something else.