What Causes Heavy And Prolonged Period After Having Protected Sex?

hi I am 24 years old and i am married sexually active but use protection all the time protection never usted i was on my regular period so the day it stopped we had unprotected sex for few minutes bu nothing happened and then we had sex with protection on and then next day i kinda start bleeding little bit only when i use restroom and wipe my self then i can see the blood in toilet paper adn after couple days my periods star again but ot very heavy and now its been 2 weeks adn it wont stop can you please tell me why??