I've been a software developer for 23 years and can relate to virtually everything you said. I am very obsessive about detail and getting things correct the first time. I also have a neurotic need to be "nice" to everyone, to never say no, to be self-effacing.

At one media firm I was carrying so much of the load my 2 fellow software leads decided it was cool to just disappear for a month with their stripper girlfriends, no offense to strippers. As the work piled and piled up they partied away in Vegas. Nothing was said when they returned. At my current job a team of 15+ people were unable to resolve a database migration issue which had been their prime task for 3 years. It was quietly dropped on my desk one morning not as an assignment but as a "favor". I resolved it but that was not enough. So that upper management would think the work was THEIRS I was asked to provide it in pseudo-code which they sent offshore to be recoded. Of course they were all given huge bonuses and recognition for this.

So I understand the term "work slut" very well.

What you have described is the American corporate shark tank, in fact it's classic. Your managers and coworkers recognize your talent, but only as an opportunity to coast along on your back. The hours you described are not just insane but dangerous. A regular GP is not going to look beyond your blood pressure and heart rate so find a psych professional who will actually listen to what you are saying. As far as "sorting things out" I tried that a few times in good faith and was just labeled a complainer. Of course when I quit everyone said "why didn't you talk to us?".

You can't change that culture but you can change industries. Put your feelers out in some areas that are not known to be so brutal and that you might actually enjoy. Smaller companies tend to have less of the BS you are dealing with. Anything public sector is easy compared to where you are now, consider getting out of the private sector. I know it's easy to say this but what are the chances you'll be with your current firm 10 years from now anyway?

And get over the loyalty thing, be loyal to yourself. Let other people earn it.