Should I quit trying to lose weight?

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So...a bit about myself. I live in the UK. I'm female, 5'9 and currently weigh 155-160 lbs (my weight fluctuates several pounds everyday).

Until about three years ago I never cared about my weight/diet, ate what I wanted, was reasonably active and maintained a weight of about 165 lbs. (I was athletic as a teenager and I have a lot of muscle mass). Then I graduated, started working and started going to the gym and inexplicably packed on 20 lbs (think it was the endless mocha and muffin breaks that did it...and the pies, I love pies...ahem).

One day I looked in the mirror, didn't like what I saw and went on a crazy restrictive diet eating 1500 calories a day gross, and running 4 miles a day 4 times a week. I went down to 150 lbs within six months. I was able to maintain this weight for a year with blood, sweat and tears (endless yo-yoing, bingeing and restricting, obsessive exercising - and probably even developed a sub-clinical eating disorder/anorexia athletica/exercise bulimia thing).

But life suffered in other ways...in particular my career is very demanding and I couldn't focus on both it and the evolving eating disorder so I had to let go and eat more. My weight crept up to 160 lb.

I decided to join MFP December last year in order to lose the 10 pounds slowly and safely and to learn about my eating and exercise habits. I set a target of 0.5lb loss/wk. MFP gives me 1780 calories a day.

The problem is that I get hungry and 1780 is noWHERE near filling enough (I envy all the 'I can't eat 1200 calories people!) I gross 2500-3000 calories every single day. Whilst I love fruit and veggies, I'm a cereal/carbaholic and indifferent to protein. I love nuts and can easily eat hundreds of grams of peanuts in a single day when I let myself. I have given myself permission to eat when hungry/give in to cravings but I have logged every single day and everything I've eaten as closely as I could. On 'hungry'/'bingey' days this can hit 4000 calories. I now practically live in the gym when I'm not working (mostly cardio, I've taken up BodyPump and some light weights in the last few months). In the last two months, I have not lost a single pound. Having said that I've not gained anything either. I've not lost inches as my clothes still fit the same (UK size 10/12).

I find myself wondering if I've come to the end of the road, and if it's time to stop logging/monitoring and just accept my current weight and food behaviour, as those last 5 pounds may never come off. Also, seeing seeing large red numbers in my food log every day gets demoralising, and pushes me towards excessive cardio to ratchet up the numbers, which has led to a spiral of excessive exercise and excessive eating. I just want to be normal again. So, how do I get off this hamster wheel?