I had very similar last year. Bloods came back as abnormal, I was further referred to colposcopy and biopsy taken but all came back as normal. 
what was pointed out to me during my colposcopy however was that my cervix was overflowing with hormones. She actually told me I was a very long way away from the menopause so overflowing with hormones I was lol.  I was advised this was what was causing my symptoms and was booked back in for cauterising.

its crazy the most random issues can cause symptoms that you wouldn’t even think of. I hope everything goes well for you xxx

Thank you for responding. I have an appointment now for next Sunday - seems so long to wait but is within the 2 weeks. My appointment is just to talk to the specialist doctor and possibly an examination but not colposcopy or anything like that. Which I assumed I’d be having a colposcopy so I’m guessing they’re not hugely concerned if not wanting me to go straight for that. 

All my swabs have come back negative.

so I will have to wait for my appointment I suppose for results.

How did you get on? I’m on the pathway now and appointment is christmas eve

Hi, I had an ultrasound scan which was all normal and also had a colposcopy and they did an extra bit to take tissue samples from my uterus. All came back normal. I got told it’s an ectropion and offered to burn it off? But I declined. I still get the bleeding but I’m due my usual smear test next autumn also so hopefully that will also come back as normal. Hopefully yours is similar. I hope you get good news.