My period came 3 days early i had unprotected sex 3 time during three weeks. could i be pregnant?

Possibly: The early period you had might not have been a true period. Wait a week and consider a urine pregnancy test. Also be careful having unprotected set if you don't want to be pregnant or contract an std.

Take a test : If you think you might be pregnant check then check a home pregnancy test. They are cheap, reliable and available at any pharmacy.