Hello there. my period ended 3 days ago, last night it from the seems of it started again... what could that be? should i be concerned and go get chec

Irregular period: Many things cause irregular periods. If you were having unprotected sex it is possible this was a mild miscarriage. It could also be due to normal life stressors. You should reset to a normal period within the next two months. If you miss your next period, take a home pregnancy test. For any other concerns please see you doctor.