Am i pregnant? HELP!?

I have done 3 pregnancy tests, 2negative and 1posative, ive had two periods since february but i havent had one since, ive put on 2stone and i look pregnant and sometime i feel something move and i have also got a faint dark line under my belly button. I had a blood test a month ago and it came back 'inflamed' so ive gotta have a scan on the 13th of july but im really confused, im only 14 and i dont talk to the boy that could be my baby's father.. i really need help!:/