Its possible to get pregnant the day before your period. My period came on not normal the night before I had unprotected sex with my boyfriend.?

Unlikely. In order to conceive you must first ovulate, then have the sperm fertilize this egg. It really depends on your menstrual cycle patterns. Do you have a menstrual cylce every 28 days like clockwork? If so, you would ovulate 14 days prior to the onset of a normal menstrual cycle. Thus, no ovulation the day before menses and no pregnancy. If cycles are irregular, ovulation can be unpredictable.