Hi Jay, welcome.
I've had one eye cross-linked, and have the other this Friday! The operation is totally pain free, although you can feel stuff, it's totally numb. I got home with a goody bag of painkillers! To be honest I felt fine, just sat outside sunbathing (with an eye patch on) however after about 5 hours the pain started to slowly creep in. Not going to lie it's not the greatest feeling in the world, but my operation was around 15:00 and pain came in around 21:00 and I went to bed at midnight, therefore just a few hours of discomfort... woke up in the morning and everything was fine, not an ounce of pain. I've heard it can go on for a few days, but this wasn't my experience, I'm hoping it'll be the same the second time round.
Your vision will be horrible and blurry for around 1 or 2 weeks. They didn't actually issue me an eye patch (I guess paying £1,515 doesn't get you that huh) but I chose to wear one most of the time to cut out all the glare. My advice is don't do too much too soon... I went to the pub with my girlfriend for a meal and a pint 5 days after the procedure and it was a mistake. This time, for the first week at least I'm staying in! Maybe go for a gentle walk with my mum. It probably helps that it's dark outside all the damn time at the moment. Your sight will start getting back to normal after about 3 months, but it can take up to a year for it to settle down completely. This may mean quite a few trips to the opticians. I'm currently waiting for a new prescription but it'll probably change again by the time I get it

Overall, you're probably worrying too much

I'm still nervous this time round as they're doing my good eye, meaning I've got to rely on my bad eye for a while... anyway good luck and pop back and tell us how it went.
Olly.