Pregnant & having your period

Quanisha
Can you be pregnant and still have your period? My cycle is like 21 or 22 days.. I get my period twice a month. I've taken pt and they all came out negative, my nipples have been hurting every day for the past 4 months, I'm always nauseous and and tired all the time and my periods haven't been normal it's either 3 days late or 3 days early.