BROWN DISCHARGE

okay so on February 6th I had unprotected sex pull out method then on the 7th I had my period they are irregular. then on Saturday I had unprotected anal sex . Sunday the 16th I noticed brown discharge now idk but it made me freak out Monday when I wipe I noticed brown but it looked a little thin stretchy on the tissue now does this mean implantation bleeding? or is this STD discharge? or just ovulation discharge when I looked it up it told me that so it made me freak out please help should I be concerned? or should I be okay