Brown spotting 11 weeks



I am 11 weeks today. Last night when going to the bathroom I noticed some light brown spotting when wiping. We did have sex about 24 hours prior. There's little to no cramping happening. It was still happening when wiping this morning, so my OB said to go to the ER. Baby was moving and heart rate of 162! That was great, and comforting. However the Dr said they can't say what for sure caused the bleeding or when it will end. And of course they can't say everything will continue to progress fine. I'm curious if anyone else has gotten spotting like this? Or how long it may have lasted?

Thank you!