You've said so much of how it feels for me too- I feel like I live my life under a rule book- it's exhausting! I have both anorexia and bulimia (though at the moment my weight isn't in the anorexic range and seems to be going up for reasons I do not understand, even after 18 years of one or the other disorder!)
I have recovered from bulimia before- it can be done. It's just not easy. I use that to help keep myself going and hacking at what feels like a massive daily mountain. (Sounds pretty depressing, feels pretty depressing!). I go through bouts where I do so well, but then the exhaustion creeps up on me and I lose it all.

I spent 9 months in treatment, it wasn't overnight so we'd go home each day and so I never really managed more than a handful of bulimia free days because I couldn't tolerate eating and then going home and still needing to eat more. I was also not sleeping and trying to keep my exercise going but still in check. I felt all over the place. It was almost a given that it wouldn't work out. I left and felt so ashamed and fed up with myself I managed 5 day stretches each week...before I landed myself in a neurotic exhausted state, and lost it all. I'm still scrabbing to get something back. I managed 3-4 days a week last month but this month seems not so good. I feel so huge- my weight went up despite actually restricting further on my apparently-"not enough" diet and it's just too difficult to not cave in. So far this month I've not managed a single day and can't see how I manage to pick myself up. I just feel disgusted with myself for gaining weight or when losing weight (through bulimia) feel ashamed. I exercise; my weight goes up (without eating more...still don't get that!) I cut back in food; I land myself an appetite I can't seem to bypass and gain weight...I guess I should be grateful I've had any grip at all on my weight even if it's through ill means.

What I wanted to say though- was that there is always a chance that things can improve. Even if you manage a single day it's a plus. It's money saved, it's teeth saved, it's a day's break and a step closer to getting a better hold on things. It wont all change overnight (in my case it wont even change over a year!) but I know it can be done and I can say has been done. Although I don't have the same set-up as before so it's not as "easy" to stop (not that it could be described as easy by a long stretch!) I do know it's possible, and the rule book thing gets easier to live with if you get into a pattern and a system. It's probably not the right way of doing things. Someone once told me if you have to try too hard at anything your doing it the wrong way, but I think if you want something hard enough, and keep hacking at it, you might not reach what you want but you will be closer than if you hadn't tried at all and that has got to be better than not changing anything.

2 days is massive- it's fantastic- its also going some to have not managed that many days in so long too. It always feels terrifying the first time in a long time when I do something like that. The idea of "feeling the fear and doing it anyway" usually gives me murderous feelings in response! It's not impossible, it just feels that way. Keep your head up and your feet on the floor.