Should I even be stressed out

So me and my bf had unprotected sex right after my period and he came inside me I think I don't have to worry since I wasn't ovulating and we have checked ourselves with the doctor and we are clean but I don't think I can get pregnant since it's highly impossible to get pregnant when you're still having brownish discharge but my friend keeps telling me I should be worried but I wiped out the sperm and showered immediately with hot water I know that won't kill the sperm but it does reduces the chances and he smokes a lot and I think he's sperm count is lower than normal and he eats unhealthy as well