16 year old female with a serious question..im scared..?

ive had my period..but now i randomly start bleeding down there...this is the first time this has happened.. i dont cramp when it happens or really even bleed alot..spotting? i dont talk to my mom much so i cant talk to her about it & im staying with my dad right now.. i wanna talk to my stepmom about it but what do i say? i mean..theres a possibility i could be pregnant but could that really be it? women, please help me out..im embarred to go into detail but to get a little more answers guess i have to..? umm...blood is kinda a light redish pink...and its not alot, just a little...any answers help.. ive never been to a gynecologist..but it looks like imma have to...thanks to all who answer!