Spotting after intercourse

18 weeks pregnant here. After namin magdo ni partner nagspotting ako bigla. I feel sore din down there. Theory ko since 2 weeks na kami hindi nagdo baka nabigla lang ulit ako kaya nagbleed? Normal ba yun sumikip yung cervix nyo? I don't feel anything hurts naman in regards kay baby, feeling ko lang nadevirginize ulit ako pero I'm still worried.