i am scared help??

hi everyone! i really need to take this out of my chest : almost three weeks ago i was with this guy : we enjoyed foreplay, i blew him and then we cuddled for 20 minutes i think. Then we started foreplay again and he penetrated my vagina for like 3-4 seconds. He immediately stopped because we didn't have condoms and now i feel so stupid because i am so afraid i coule be pregnant for that few seconds penetration. (i read that some sperm is alive in the male urethra) i don't even know if i was in my fertile window that day because i have irregular periods (haven't had it since may). i have no breast pain, i just feel nauseous sometimes but i dont know if it is anxiety and i feel tired and feel stomach bloat. I know i have been stupid and only a pregnancy test can tell the truth right know but maybe i just need to talk to someone and get some opinions because i feel very alone in this. hope someone will help me. Thank you!