I had my tubes tied six years ago, but missed a period, could i be pregnant?

im 15 years old and usually get my period around the last week of the month. My periods are for the most part very consistent. Around December 12th I had sex with my boys friend (unprotected) and he tried using the pull out method but say he did in time but also isn't positive and there is always a chance of precum and the next day I started my birth control. I am 10 days late on my period and have been feeling very bloated, some what vivid dreams, sore boobs, back pain, feeling tired, and loss of appetite. Today I missed my pill but just very light amount of brown discharge but it ahsnt came back and doesn t even show up when I wipe. Could I be pregnant or is it my period?