I can relate to that - when my workload gets too heavy, it stresses me too. And yes, my way of coping was to eat biscuits by the packet - so now I'm insulin resistant and was headed towards diabetes! Just something else to cope with.
Things I did:
Decided that good enough was good enough, everything didn't have to be perfect. There's a saying (Pareto principle) that you get the first 80% of a job done in the first 20% of the time and then it takes you the remaining 80% of the time to do the last 20% of the work. If it ain't life threatening, maybe 80% will do sometimes.
Talked to my boss about the fact that I was working so long I wasn't sleeping enough, let alone having a life and got some reallocation of my work. He wasn't odd about it either, which I was worried about. In fact, he was amazed how much I was doing and agreed it was too much.
Broke my work into bitesized chunks (30 minutes) and gave myself a break - make a coffee, walk to find someone rather than phone and then made myself take proper breaks and lunchtimes - went and sat with other folk for lunch instead of in front of my computer. It actually made me work better and faster while I was working.
Finally, like lots of the advice here, I got some exercise (walking for 30 mins a day) and kept off the booze, both of which made me sleep better when I did get to bed.
Incidentally, the more hassled you are, the more 'processing' your brain needs to do at night, so the more REM sleep and the less 'recuperative' sleep you do. So you wake up tired.
To break the cycle, you need to chill - see above!
Take care love, you owe it to yourself to sort this out. Everyone is very hot on 'work/life balance' these days, so I think you'll get a sympathetic hearing if you go and talk to someone.
Good luck, Jay