Missed Periods Post Sex, On Yasmin, Had Taken Plan B Post Intercourse. Pregnant?

i use to be on birth control pills but financially im unable to pay for them due to going to college til october i had stopped for a month decided to go on condoms ... Which on the 24th of april me and my long term boyfriend of almost 3 years and living together, had sex and realized after that the condom broke, so the morning (25th) i had went to the walk in clinic and had gotten a similar to plan b and i took it. then on the 26th me and my boyfriend had sex again and the condom broke again!! really stupid. and I took plan b after my college school is done today, (27) between 3-5 to take it. The doctor had given me two 28 day pack yazmin birth control pill. Since then I ve been changing my birth control due to the doctors.. I m on my last week, second to last day of the first pack and I haven\t had my period yet but the week after i took plan b the second time i had gotten what it seems like my period on the 2nd of may and it last til the 5th. Haven t had my period since then....Could it be thats its stress , new birth control, plan b side effects possible pregnancy?