Eugene, some excellent insight from the other posters in this topic, so I'll just add my brief comments.
We have (or are) all been here. I'm in my last half of my life in this profession and a few things are really becoming clear. I think most of these apply to all of us:
1. there is no shortage of work in most areas right now. The main goal for everyone now is not getting work, but weeding out the bad work so you can spend your time on good clients.
2. A lot of work out there is just not worth doing by anyone. Either someone is not willing to pay for it, or they are asking for things that simply cannot be profitable or worth doing for anyone at any price. Learning to confidently say "no" is an ongoing skill set I think all of us work on our entire careers.
3. Take vacations - even if they are just occasional 3-day weekends. These really give (me at least) a chance to evaluate what the hell I'm doing and what the hell I want to do. It was during a 3 day beach outing with the fam' I realized I needed to dump a client that was zapping 70 percent of my energy and time and only contributing 20 percent to my income. It was a tough pill to swallow, and I had my doubts the following few months after dropping the axe. But ultimately it made room for new areas of work and great customers.
4. within your own company: reward the good folks, but don't be hesitant to oust someone who is dragging everyone else (including you) down. It's amazing how one person can poison the well. Anyone who's run a biz more than 10 years knows exactly what I am talking about.
I really cant' stress the importance of #1 enough. There are many jobs simply not worth taking. And people can be really pushy. My natural inkling is to help nearly anyone, and I constantly fight to stay in the drivers's seat. Deadlines are ever present in our line of work, and it's easy to fall into a vicious cycle of bouncing from emergency-to-emergency. This kind of environment destroys your own ability to remain sane and make your own operations efficient and work for your own needs.