Sex an pregnancy ache afterwards

A little Tmi but today was the first time that my husband an I did anything since we found out. Im exactly 17weeks today an im a little nervous because afterwards I felt just this dull ache throughout my lower belly an I still feel it just off an on but there's no spotting (knock on wood) im just still nervous though I feel like is it normal for this to happen or did we hurt the baby? Anyone else have this?????? Please put this expectant mommy at ease