Suggest Remedy For Delay In Periods And Cramping In Stomach

A month ago I had Tonsilitis and i was on antibiotics along with my birth control. I continued to take my pills faithfully and 1 week after i finished the antibiotics, i had protected sex. According to my pack, my period is supposed to start this week but I havn't seen any blood and i am cramping. Not to mention, i have a yeast infection right now as well. Is it possible that i'm pregnant or just paranoid?