Bleeding after sex, second trimester

I am currently 24+ weeks pregnant and me and my partner had intercourse a couple of nights ago, since then I was wiping pink blood till this morning, I went to see my midwife who referred me to the hospital to go and get checked out. At the hospital they listened in to the baby's heart beat, everything was normal, they took swabs from my vagina to see if I have an infection ect as I am irritated down there and some itchyness. Since I have been home I have been crampy, mild cramps so I don't think it's anything to worry about but has anyone experienced this? The cramps almost feel like minor period cramps.