Oh Julie, how I sympathise! I was in such a similar situation, really struggling to stay within target, then we went away several times in quick succession, and I went out of target range.
I wasn't worried at first - I'd done it once, of course I could do it again - but I just COULDN'T manage to get back. I never was more than just a few pounds over target, but it was costing me a fortune, and, in the end, making me thoroughly miserable.
I'd restarted keeping a food diary, keeping track of all my syns, but in the end it became SUCH a burden that, if it hadn't been for Hubby, I'd have definitely given up. Like you, I had expected it to be FUN to maintain, enjoying making the 'right' choices, and putting all that I'd learnt about food optimising into practice.
Instead, I seemed to become almost obsessed about food, worrying about it all the time, feeling guilty when I slipped up, to the point where I really felt that it was spoiling my life!
Fortunately, Hubby - who has also struggled during the year and a bit that he's kept to target - was very keen to keep going to classes. He feels that if we stop going, without the discipline of the weekly weigh in, we'll both be back to where we started in no time at all.
So, eventually, I had a word with our Consultant, explained how I was feeling, and we agreed on a new target. I hadn't realised that, although this raises my BMI figure, it is entirely down to you to set your target weight. If you would be happier with a higher weight, then, whatever your BMI, that's fine. (Although there are LOWER limits!!!).
So, that's what I've done, and it was like a huge burden being lifted off my shoulders! I would advise anyone who is feeling as I was to seriously reconsider adjusting their target to a more comfortable and manageable and MAINTAINABLE level, regardless of your BMI figure. I'm sure that others will disagree, but I really WANT to keep going to classes, and WANT to keep the 4 stone I've lost in total (not all with Slimming World!) off for good.
OMG, what a rant!!!