Help? Placental hemorrhage 2nd trimester

I was in a car accident november 1st, and hit my stomach during the accident. I had started seeing some spotting on Christmas eve and it didn't stop until Saturday. I went in today because I have been having bad cramping for weeks and just didn't feel normal and the bleeding made it very worrisome. My doctor called me later on very concerned but I wasn't able to answer the call. I called in and reached a nurse, whom told me that my placenta is low lying. There is also a small hemorrhage noted in the placenta. She told me I need to be on pelvic rest and bed rest basically and that if I try to do anything I could have a miscarriage. I am very sad and just upset that I had been complaining about pains but no one took me seriously until this ultrasound. I am wondering if this is related at all to my accident or if it is just a coincidence. I was almost 7 weeks during the car accident I am now almost 15 weeks finding the hemorrhage