I wouldn't say you were paranoid but lots of women, and men, get very anxious about pregnancy after having sex.
It is too early for ANY symptoms of pregnancy. You WOULD NOT even be pregnant yet, if you were going to get pregnant. It is NOT immediate but takes several days for fertilization and implanatation (when you truly are pregnant) to occur.
You used protection. The chances of pregnancy are VERY LOW.
Hope it helps.