Had Unprotected Sex, Creamy And Brown Discharge, Pregnancy Tests Negative. Concern About?

Hi i had unprotected sex on the 21st off December & 26th, my period was the 8th off December i usually have really heavy periods usually wear a tampon& a pad have to take pain killers, but inwas due for my period o the 4th off January it came to the 3rd i had what inthought was a period pain but didnt come on, the next day i got some brown with a bit off blood , but irregular times off the day for 4 days, not even enogh for a tampon, then i started getting like a creamy/beigy coloured discharge what had abit off a odor not foul smelling though, then i started ettin watery sort off discharge which was kinda off milky lookig, i have took four pregnancy test all negative, but when i was a child i use to have really bad water infections which when i use to go to the doctors never shown in my wee it had to be grown, i just dont feel like myself going threw this any advice? Aswell this was not planned i do not want a baby