Missing my periods ,HPT NEGATIVE

Patient: Me and my BF had sex on the 3rd day of my period and i took i pill just after 8 hr(21 march 2014). after that we had un protected sex 3-4 time but he never discharged in to me. now i missed my period in 21 april 2014 now its 7 may 2014 . .. am i pregenent ? please adviceplease suggest how can i start my missing periods.i an irregular in my periods by 2 to 10 days earlier.these days i am in stress due to some family and study issue can it be a reson for delay in periods.?

Symptoms: took 2 HPT negative. some white creeme discharge, some time white discharged, cramp on thies, lower abdomin,