I've been diagnosed with BPD about 8 months ago, and am currently finishing up DBT, and even with the skills learnt there, I'm still having trouble keeping my destructive thoughts from overwhelming my decision-making abilities. I've had eating disorders for the past 7 or 8 years now, and it got progressively more exacerbated since the BPD diagnosis, to the point where people comment on my weight loss now... There are days when I do genuinely want to get better and get help, start eating and living like a normal person, but in the back of my mind, there is always that little voice telling me "You know you're just lying to yourself, you don't really want that, getting better means getting fat". Most of the time, those thoughts really overwhelm me, and all my plans to eat normally that day go flying out the window, and I feel like a mess, even opposite action won't help, my brain just...decides I don't want to eat and nothing can make me do it. 
It's really tearing me apart, because I really thought I would get better after DBT, and in a sense, I did, I acquired skills to deal with certain minor things, but it feels like it just gave the EDs more room to take hold in my mind.
I do want to get better, and I do want to get out of the ED cycle, but I just can't seem to do it. My psychiatrist is aware of that part of my history, and did warn me that if I don't stabilize I'd get pulled off my ADHD meds (which do exacerbate the EDs, as they're appetite suppressants, but I also need them to function at work). 
I was wondering, does anyone else here experience the same thing, and how do you guys keep your destructive thoughts in check?

P.S. : Sorry about the long rant and if anything is unclear... 