I started my period but had signs of pregnancy the whole week before. Is it possible to be pregnant?

Yes, a woman can still be pregnant while having spotting or breakthrough bleeding that she confuses with a menstrual period. This bleeding is sometimes associated with an early pregnancy and is referred to as implantation bleeding. If you believe you may be pregnant because you may have been sexually active in the two to three weeks before your signs of pregnancy started, then a pregnancy test could confirm.