Abnormal bleeding and back pain

I've been having painful sex for a few months now and some bleeding after. My last smear test was over 2 years ago, all normal. 
I made an appointment at the GP and was given tests for STIs and bacterial infections - all clear. The GP won't give me another smear as it's not due until October. 
I've now been referred for an ultrasound but this isn't for another month. Since have the swabs taken I've been spotting everyday and have continual lower back pain. I'm having trouble sleeping and constantly crying because I'm so scared of what it could be and it just seems like such a long wait. 
 

Has anybody experienced anything similar and what was the outcome?