We're reading J2, don't worry, and we're behind you 100%! Good luck!
Do you think 5st weight loss by Christmas do-able tho, quite a lot to lose in 5 months, a stone a month (20 weeks left, 3.5 lb a week)?
I'm don't mean to sound negative and that you can't do it, I believe the human spirit can achieve ANYTHING it sets it's heart out to do. But, I have recently changed my thinking to slow and steady which has given more confidence and assurance to go on (only 5 days in, mind).
I'm just saying as I've set myself unachievable targets (over and over) and dropped out (over and over) when not been able to achieve it, even early on. I'm not saying that yours are unachievable, everyone is different, just something to consider?
I wish you every bit of luck, sorry for the essay!