Hi.. i had unprotected sex on april 29 & 30. I had spotting on May 3.

I also had 2 days mild bleeding/spotting on May 15 & 16 and starting to have same symptoms of pregnancy and frequently urinating.
I'm expecting my period to come on May 18 however it did not come until on May 23 i had mild bleeding (pinkish to brownish blood) same on the next day May 24 and now, May 25 i am bleeding just like a normal period but with no clot. I've never experience this in my entire menstrual cycle. WHAT COULD THIS BE? PLEASE HELP. I am 27 yrs old.