no discharge no nothing on expected period day

how come my underwear is like litteraly dry like there's just a littttle bit of white discharge but no blood? my period is supposed to come today but i had a 5min long unprotected sex on July 22nd which was a fertile day but he didnt finish in me..but i heard you get more discharge than usual when youre pregnant so this is really weird..and i havent had any symptoms, either pregnancy or PMS. my period in July came a day late cause of planB but idk why this time its not on time..can just one pill delay your second period after taking the pill too? this is what i've had the whole day