Colposcopy after hysterectomy biopsy CIN3

I had to have a hysterectomy in February just after I turned 27 due to endometriosis and the constant pain I was in. My doctor agreed after my second child that it would be done because after 11 years of pain I couldn't bare it anymore.

My cervix was removed in the process and a biopsy was done and came back that there was CIN3 on my cervix, they called me in for swabs to check it hadn't spread. Today I got a letter to say a urgent referral has been sent for a colascopy after the swab results, unfortunately the letter didn't go into any details just that a urgent referral was made and tissue may need to be removed. It doesn't even say where or when. 

Can anyone give me a idea why? I just need to know if there's a chance it has spread etc, it's the not knowing that's worse for me because I can't prepare myself .

thanks xx