bleeding during second trimester

Sarah
Hello, 
Anybody out there that has been bleeding during their pregnancy? 
Last week I went to the ER since I had significant bleeding that lasted three days then this week same thing.. Went to doctor who sent me  for an ultrasound.  Awaiting results as I type this. Baby looks good and cervix looked good. What gives? Anybody been through this? Been having minimal cramping no tissue being passed. 
​-stressed