Amanda - loved your post, and I concur with the others - it IS a cyclical thing. The weight gain is cyclical too.

to you for recognizing it NOW and wanting to keep it in check even though you are frustrated.
One thing that I have noticed points back to Jay's first post. Whenever I am "stressed", my weight goes up, and I get in a funk. It becomes a spiral if I'm not really careful. And I use the term stressed very liberally - it can be from work, weather, frustration, post-holiday blues, too much physical stress on my body (are you working out TOO much, or lifting TOO much?).
I find that what turns me around the fastest is:
1. Balance - make sure I am playing enough, praying or meditating enough, and ENJOYING all aspects of my life as much as possible.
2. Indudge that sweet tooth - but be smart about it - healthy, sugar free banana bread for example. Life is too short to not "enjoy the journey". What are some healthy things that make you feel good - you know - really good. Thiings that make you feel like you are cheating on your plan? Indulge in a few more of those.
3. Remember that life ISN'T fair. No, I can't ever eat like a normal person again. Then I kick myself hard and remind myself that - like you - I have many, many blessings in my life - things that OTHERS struggle with. We all have things in our life that challenge us more than other people - but their challenges are just different. Our's happens to be food. But, in the scheme of things - we are very, very blessed. We get to eat food every day - we don't have to give it up. We get to choose what we want (we can afford the luxury of choosing from so many, many healthy things). We are really blessed indeed!
4. Vary my exercise routine for a bit - that usually jump starts the weight loss (not necessarily more - just different) Add in some variety - yoga, dance, balance ball, sports - anything that challenges your body in a new way.
You WILL get through this, and your body WILL respond.
And for that changing shape (mine was from menopause), I found that making sure my diet was balanced (plenty of healthy fats - MUFAS, and protein - really keep those carbs in check) and the right balance of many different exercises eventually helped me reshape those pesky areas (including my enormous backside and hips).