At the time, like a frog in warming water, I constantly normalised it - working 20 hours a day for a year isn't stressful, it's heroic! I enjoy this! I thrive on stress. The booze? Oh, that's just to help keep me awake.
About four years ago I stopped eating and sleeping properly - I mean, previous to that I hadn't done either properly either, but four years ago it ceased to be voluntary. I lost huge amounts of weight. I told people I was on a diet. I started having bouts of delirium and puking that would put me out of action for days or weeks on end, unable to sip water even, slipping in and out of sweaty consciousness. I told myself I was just really unlucky with food poisoning.
About six months ago I just stopped - couldn't go on, couldn't face another day in the hell I'd created for myself, stomach knotted from anxiety and hunger but not hunger. Went on sabattical. Watched mountains for months. Read. Cried. Ranted and raved. Began to heal. Got medical help. Discovered that I had given myself a stress driven syndrome not really seen since children in fucking Victorian workhouses - cyclical vomiting syndrome.
Gave notice. Sold equity to company, made orderly transition. Three months on, I'm still coming to terms - beginning to remember wanting things, having desires, not feeling like every moment not spent working was a betrayal - being able to feel something like joy. Above everything else, I haven't puked in months and I'm even beginning to have to watch my weight.
The main thing I've learned on reflection is that I did this to myself. I chose roles and responsibilities that crushed me, and I failed to emotionally disinvest in the company as it grew. I also habituated stress to the degree that I didn't even perceive it as stress, and denied it to myself even as I ground my teeth to aching stumps. In hindsight, I can of course aim to not put myself in the same situation again, but at the time I had nothing to really check my reality against. People around me were supportive - but rather than saying "hey, you're killing yourself", it would be "want another coffee? Need smokes? You work so hard." - so essentially enabled the behaviour rather than confronting it. There's an almost dangerously cultish obsession with industriousness in our society.
I digress.
The other thing I learned that I hadn't really understood was that stress can ruin your physical, not just mental, health.