Bleeding after sex, heavy periods and back pain.

Last  year my smear showed up cgin, cin3 and smile, after 2 lletz treatments I finally got clear margins. At the start of this year I had my 6 month smear which thankfully came back clear. 

Since the lletz treatment (last one August 2016) my periods have been strange, lasting a lot longer and a lot heavier than before but also start strange, only way i can describe it is it's like there's a blockage for a few days then its like a plugs been pulled and the flow is then really heavy. 

Ive also been experiencing bleeding after sex which seems to be getting worst. 

I did mention all of this when I went for my smear, they tested for infections but all came back clear, they said it would hopefully clear up as I'd had the smear going higher into my cervical canal but if it didn't I needed to request a gyne referral. 

The first few periods since my smear were better but now back to slow starts and heavy bleeding after a few days. 

For the past few weeks I've also had a very painful lower back. 

Has anyone else experienced similar?