Thank you for putting up your problem to Healthcare Magic!
The precum may have sperms and can cause pregnancy
, and withdrawing before ejaculation is also not safe practice against pregnancy.
The symptoms you are having are probably psychogenic due to fear of getting pregnant and the symptoms of pregnancy do not come the very next day.
Please get a urine pregnancy test after 7-10days to rule out pregnancy.
I hope this information would be both informative and helpful for you