pregnant or infection???

So i had my first smear in early July and got told I had CIN3 and had to have LLETZ procedure. I had this on the 28th July and have since been told no further treatment is required and to go back for check up in 6 months. 


I had no bleeding after the lletz just the watery discharge. I did get an infection in the first week but this was cleared up with antibiotics. 

Anyway me and my partner resumed our usual sex life 4 weeks after as the discharge had stopped. 


We are trying for a baby (I checked with the colposcopy clinic whether they would prefer me to wait until the 6 month check up but they advised there is no need).


So we did have sex 5 days before my colposcopy treatment when my copper coil was rremoved so there could be a chance I could be pregnant from then, although I have had a period since (it was very light and short, not like normal but this could be due to me having the coil for the last 4 years which can make periods heavier or it could be due to pregnancy?). Anyway I have felt sick and really tired and now getting this burning sensation in my pelvis, it's not unbearable, it's just uncomfortable... apparently these are symptoms of early pregnancy but I have done a test yesterday which said no but maybe it's still too early to detect?


I don't know whether this could be an infection from the lletz,  has anyone else experienced a burning sensation 4 weeks after when sexual activity resumed?