Working is not bad. But only working can prove bad. Take time and have fun. It can be with your cubicle-mates or teammates or friends at work. Looking around and having good time with your mates is a lot important as that of you meeting the target dates. A crossed target date can be compensated, if you really wish to do so. But you do whatever you can, the lost health cannot be brought back. And when you are ill, its not the target date that comes for your rescue. Its the smell of the medicines that surrounds you, does not matter whether you like it or not.
Its always better to be occupied with work when you are at your work place. But add some social bonding to it, because doing so can refresh you at any time you want. This might appear a bit being selfish, but be selfish about your health as rightly as that of you be selfish about your work. Its nothing wrong, I think. Remember to have a walk around and have fun with your mates in your and their free time. And if the free time is not available, then make free time. Making time might be difficult but making free time to have fun is not difficult. Try it out and it will work for you too as it has been working for many a people over all these years across the globe!
Work lets you earn, be it money or fame or name. But do not let it earn bad physical or mental health for you. It is work and it shall be worked in such a way that you work for yourself too at all point of times. Be selfish, if you have to be. And have fun.