Fell at 21 weeks

FTM im so anxious something is wrong. I was running up the stairs and tripped. I felt fine but after an hour I got a tight feeling and ended up going to ER. They didn’t seem to concerned, I was worried about the placenta detaching but she said it most likely didn’t happen, I would have bad cramps and bleeding, had an ultrasound & his heartbeat is all good.

I even booked a private ultrasound and she said everything is perfect, she was doing an anatomy scan and she told me she could see the blood flow through the placenta. I can feel him kicking so I know he’s okay I’m just worried if the placenta could detach later on or something? I noticed my stomach does feel a bit tender when I press down not enough to cause me any pain but i definitely notice it.

I am an anxious wreck rn I don’t know how I can calm my nerves