Slight bleeding at 5wks 4 days

Is it normal to bleed after inter course during pregnancy?? I started bleeding yesterday morn after my DH had inter course the night before. I am very sore even went to the ER when I realized the bleeding hadn't stopped. Is very very light and I only see it when I wipe. They wouldn't do an ultrasound at the ER because they said it was too early to see anything. Please help I am freaking out. I have had 2 healthy pregnancies and not experienced this before.