I was in a similar situation with my first smear and I know it's not easy but all I can say is try not to panic - I had my first smear and then had a call from the hopsital inviting me to an appointment wtih a consultant in under a week and I freaked out - I had no results from the smear, no letter, no nothing, just a call from the fast track referals department.
The best thing you can do is, if you still have any information for them, call the colp clinic you'll be attending and see if they can tell you anything - I rang my GP when I got my letter and got the worlds most unhelpful receptionist who said 'well IIIIII don't know why they've called you WE don't have any results'. You'll probably get you smear letter through on Monday (mine came the day after I had the call from the hospital) but try calling the colp. clinic all the same.
It could be something as simple as you've tested positive for HPV and they just want a double check (apparently they always do a colp for any HPV positive smear, even if there are no changes) or you could have an abnormality. Try and bear in mind though (this may help keep you slightly sane - I know how panic can take hold!) that even if you do have some changes they're really really likely to be borderline or mild if you had a clear result 6 months ago. And don't worry about the shortness of time until the colposcopy - in my case it was just that that was the earliest available time and I was next in line, it's just as likely I could have waited 2/3 weeks.
I hope you get on ok over the weekend - you could try the clinic today but I don't know if they'd work saturdays - otherwise call first thing Monday (and maybe try your GP too, hopefully you have a nice receptionist!! haha) they should be able to put your mind at rest x x x x x