I had unprotected sex during my regular periods and then i took the morning after pill can i still be prgnant ?

Maybe. Maybe not.: Plan B and other emergency contraceptive pills work the majority of the time, but not all the time, so should test in 3 weeks. A urine pregnancy test done correctly gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened). If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and therefore lead to a repeat test.