Pregnant or Not Pregnant

So me and my boyfriend have been dating for 8 months now. I went to a homecoming dance and afterwards we had sex. I got home and I was bleeding like a normal amount of period blood. But I haven’t had my period for the last two months because of my birth control. I took four test. Two came back with a faint like looking like they were positive(I took the blue one step). And I took two more and they were negative no faint like at all(pink one step). I’m not having any pregnancy symptoms and I’m bleeding just like my normal period. Should I be worried?