I had unprotected sex a few weeks ago and i started my period later that same day. now in the same month i'm having bloody mucus what is this?

Bloody discharge: It is assumed that the "period" you described as "the next day after sex" was a month after your previous period. "Bloody discharge" can indicate irritation, or the onset of your period. If this turns into bleeding, and resembles a period, it probably is, but if you feel lethargic and bloated, you should obtain a serum (not urine) pregnancy test. If positive see your physician soon for advice.