Just been diagnosed with stage 1b after loop diathermy

Hello everyone 

I had the news yesterday following my loop diathermy 2 weeks ago that they have found cancer in my cervix at stage 1b, i have an mri scan on tuesday. My question is i have severe pain in my pelvis on the left side that was diagnosed as sciatica and im now convinced it is related to the diagnosis. Do you think its possible for the stage 1b to not actually be stage 1b after an mri? Because at my last colposcopy it was only cin3. I am really worried that its much bigger than what they think and am panicking alot. Please help! Many thanks