My first suggestion would be to stop feeling guilty when you make a mistake. Yes, you'd like to make as few as possible, but you're trying as hard as you can under the circumstances, and you're human, and no human is perfect. We all make mistakes sometimes, even the best of us, and schedules often slip as a result. So, relax a little. This doesn't mean you stop caring; it doesn't mean you stop trying to learn from your mistakes; it just means you don't feel guilty about them.

Secondly, try to get as much rest and exercise as you can. This is very important.

I do agree that you should complete your promised deliverable; it's the right thing to do. But after it's done, do see if you can get two or three weeks off, at the very least. You know you're starting to burn out, and it's not in your employer's interest to burn you out completely. (Point that out to them if necessary.) If your finances allow for it, you could perhaps take an unpaid leave of absence.

I walked away for 2 years about 10 years ago. I was totally burnt out. If I had taken time before that when I first started to get burnt out, I think it would have taken less than 2 years.

While it is nice that you have loyalty to completing a job you have undertaken, remember that is never a two way street. Situations being right, you can and will be cut loose someday- recognize that and determine when it is ok for you yourself to walk away.

Was the work or workload any different at your next job? How did you manage everything for 2 years without work? Also, I've had three < 1 year stints in my 4 year career already, and this would be another one if I cut loose. I don't want this trend to continue forever. It doesn't look very healthy to me.

The work and the workload at the next job were more or less the same. I just needed time to regroup. I had lost all interest in computers.

In my case, I didn't realize I was burnt out at first... I got laid off as a result of the 9/11 terrorist attack ( short version... company lost phone and internet, was in the 'frozen' zone... etc ).

So I had unemployment, extra unemployment because of how I lost the job and I bet a lot of money on a couple super bowls and a world cup championship and made a bunch of extra money.

During those 2 years, I mostly just... hung out with friends, drank, practiced guitar, played in a couple bands, lifted weights and did some kung fu. After those 2 years, I was ready for programming again.

Burnout sucks, and it can be hard to deal with. I began work on my startup in my spare time in college because it was fun. Once I jumped into it full time it turned my life on its head. After several months I was tired of working solely on my product, and I was tired of being at the computer in general. To gain perspective, I unplugged for a while. I read more books. I took up running again. I watched talks on TED.com and rediscovered movies and TV shows. Most importantly, I began coding stuff for fun again -- stuff that was totally not related to work. I felt guilty at first, but I ended up being far more productive in the long run.

It turns out it's the little things in life that keep you sane.

Are you a founder? Do you hold a significant amount of equity? If so, you have the power to chill out and take some time off. If not, you should remind your employers that you are a human being who will work reasonable hours. Maybe that means extending your deadlines; maybe it means they need additional developers to help handle the work. The bottom line is this: if you aren't being compensated the same as the founders then you should not be expected to have their level of dedication.

You know there's a famous maxim from Lincoln that if he had two hours to cut down a tree he'd spend most of the time sharpening the ax. The best cure for a burn out is to sharpen your ax by taking time and figuring out what excites you. I'd advise you to see what non-programming things inspire you and then bring that passion back to your work. Also despite what everyone tells you having a personal life isn't a bad thing...

The problem is, working with a startup has so far meant giving up my life - and just working 24x7. Not a healthy trend, but I don't know of a startup that works otherwise. I believe I'm not very comfortable telling my boss - "I can't do this". He's the founder and this is his dream after all. I feel I'm not doing my job if I don't finish my work - no matter how long it takes. Am I obsessing unnecessarily?

I would suggest picking up a sport(insert some form of physical activity). By working more hours you are not necessarily providing the startup with more productive hours. The longer the hours the more burnt out you will get. This will result in more mistakes (bugs), more time spent trying to solve problems etc.. Do not feel guilty for taking some time out for your own life. Not only will this help you, it will help the startup. It will give your brain time to reset and you should even see an improvement in time it takes you to do tasks. Even just taking time out of the office for a decent lunch break will help make your afternoons so much more productive. The number of times I have walked away from a problem to go for a walk (anything else but sitting at the desk staring at the problem), to come back to the problem and know exactly what is wrong.

It's not only not a healthy trend, but it's a counterproductive one for you. You're at the stage in which working more is not going to help the startup, due to burnout, and the only sensible option is to work less.