Many of us are apprehensive of this procedure, myself included, so I can sympathise.
Many hospitals have different bowel prep procedures, I myself have had Picolax for both of my colonoscopies, and the first time was fine, but the second time I did struggle towards the end of the prep, I had quite a bad reaction, but I was very tired, hadn't eaten for ages, the meds I have to take don't sit on an empty stomach very well, and there was an hour slot where I thought something bad is happening here, but it did pass and I was able to get through the prep. Another factor for the bad reaction was my health and fitness had deteriorated since my first colonoscopy, so I was a lot weaker than I was. The prep is the worst part of it, make it through that and you've done the hardest part.
As for the colonoscopy, are you having sedation? I recommend it as it just makes the procedure much easier to deal with. Honestly, I was led on my side, watching the whole procedure on the screen, even saw them take biopsies. I felt relaxed all throughout it, and only experienced some discomfort, which is relieved by passing wind, so my advice is don't hold it in, let it out when you need to, it really does help. Before I knew it, it was all over and I was out, and couldn't wait to eat something.
Drink water and plenty of it, I'm not fully clued up on moviprep, but all these bowel prep laxatives pull loads of water through your bowel, effectively washing it out. It's better to drink too much than too little in my experience.
Luckily my last colonoscopy came back fine, no problems at all other than internal haemorrhoids, even the biopsies came back clear, so I shouldn't need another one for quite some time.
I'm a total wuss when it comes to any type of hospital procedure, and my anxieties went through the roof both times, but if I can make it through two, I have no doubt you'll make it through yours.