No Not at all. Unless you had unprotected sex. You would know after 4 months if you were pregnant. I mean your body would be changing, your belly would indicate something for sure. Why don;t you take a pregnancy test to make sure? At least once you've eliminated pregnancy then you can see what else it could be. When did you start your period for the first time?
I'm 16 and this happended after the first time I had sex where I skipped for about 4 months but then my boyfriend and I thought I was pregnant so we haven't had sex in FOREVER but there is no possible way I could be pregnant correct?
It could be VARIOUS things. This is something you need to take up with your Dr. He/she will have to run tests to see why you are having irregular periods...