I had that procedure some years ago. I remember reading people's experiences and feeling a little nervous, but it wasn't bad. Seems like I remember someone saying to take a couple of Advil beforehand, which I did. There was one sort of crampy-pinchy moment where the nurse held my hand, but that part was quick. Best of all, my results were normal. Hope it all goes well for you!
I'm an OB/GYN - mostly it is like having a pap smear...there is a moment where there is a cramp and for some (especially woman who have not had vaginal births) the cramp can be intense - but it is VERY quick (like 3 seconds quick)