You have unprotected sexual intercourse and each time the man releases inside of you. You think you may be pregnant but the day you are suppose to get your period u bleed but not how your regular period be. What does that mean?

It means you should see your Gyno if you are unsure or think something is wrong.
Start with a home pregnancy test.

"Periods" that are shorter or lighter than your norm can be a possible sign of pregnancy, especially since you have been having unprotected sex. As nikosmom said, maybe give it a few days, see if it is just an off period, then try a pregnancy test if you are concerned.