Megan, I can so relate to how you are feeling, because that's where I was in August. I did SO well during my hiking vacation in July - I hiked crazy mileage and ate everything in sight, came back, and weighed in at 113. No weight gain at all. The problem was, I got a little TOO used to eating more and had trouble reining myself in. Then, I went to vist my family in early August, didn't work out all that much, and ate way more than I care to admit to, and came back at -- 125!
OMG, how was that even possible?! (it was) I tried to get back on the wagon, but struggled terribly with carb cravings and the weight simply wouldn't come back off like it usually did. I would be good all week, then fall hugely off the wagon on the weekends, undoing any progress I made. It was a vicious cycle and I was very discouraged.
Finally, I just mentally got back into a "do or die" mode. It was a combination of things, I guess -- I couldn't stand seeing daily weigh-ins in the 120's; my clothes were getting tighter and I didn't like the way the bloat looked; and probably the biggest reason is that race season is coming up and the extra weight was making my runs slow and tortuous. It was significantly affecting my running performance --it was awful. I had to get into the mindset that I had to go on plan and stay on plan until I was back down to where I wanted to be. Period.
So, that's where I am. I've made working out and staying on plan one of my top priorities and was able to finally detox from those carb cravings. And it's worked. But I had to get back into that "nothing is going to stop me" mental mode. And nothing worked until I did. I'm still not "there" yet, but I'm getting there. I wish it were easier, but it's just not.