It's really daunting isn't it, when you hear there are abnormal cells inside you, and its so hard not to think the worst. The colposcopy is such a scary thought, but the reality of it is so much easier. Both times I've gone, I've been absolutely terrified, and I've come out of it both times feeling absolutely fine. I'm feeling the same now about my pending treatment, I'm really teary, but I know I'll come out of it feeling ok.
I do the very same as you in that I've played it down to my partner and mother and acted like I'm not worried, but in my mind I'm thinking a lot worse. I guess its just natural. The waiting is just horrible! BUT, it does pass, its only a short time out of your life in the grand scheme of things. Finding other things to concentrate on is best, easier said than done I know but unfortunately we've no other choice but to wait... :-/
I hope your appt comes soon and goes well. The odds are in our favour.