Could I be pregnant? Please help?

I'm supposed to start my period between yesterday and tomorrow.... I'm still a teenager and my cycle is all off. I have a suspicion that I might be pregnant but I've been putting a tampon in in case I do start. And I've seen very small traces of blood in a yellowish like secretion... Could I be pregnant of is my stressing prolonging my period from coming. Is there anything I can do to to make my period come if it's going to?