Am I pregnant?

heee .
I'm an 18-year-old girl, I'm almost 3 weeks overdue, and I've taken 4 pregnancy tests, one of which shows a positive result (very faint line) and the other 3 are negative. I also went to the doctor and had a blood test today; I'll get the results tomorrow. I don't really have many symptoms, I just have a weird feeling down there, like my uterus is giving little twinges, it's a weird feeling hard to explain. I'm also very tired and always hungry . What do you guys think, do you think I'm pregnant?? I'm so nervousggg