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.