Your bleeding could mean that your period is starting up or if you've been having unprotected sex then there is always the chance of pregnancy. Have you taken any tests to see? If you've missed your period then you can take one and more than likely get an answer that way.
If you have irregular periods then you may want to start tracking them so that you can kinda try and figure things out a bit better.
since i started my period, i either have one or not. there is no starting up, at least not with me. my boyfriend and i have been having unprotected sex, and there has been no pregnancy. i havent gotten pregnant since i gave birth to my son 7 years ago.i do have irregular periods, had those since the day i started when i was 12 years old. when i start they go on till its over for sure. either that or i dont have one, its nothing for me to miss newhere from one to six months.