To be honest, I used to worry a lot during my younger years about anything and everything, to the point of getting panic attacks and really bad headaches. But as I got older, I tended to worry less - even though I've had my fair share of problems - I eventually got use to it all, and was able to cope with the difficult and demanding types.
Sometimes, I suppose problems can arise, if you can't see light at the end of the tunnel, ie there's problems every which way you turn. I suppose you need to tackle your work related problems and see what you can do to resolve them. But stress is often a funny thing ie being unable to sleep is a sign of that, and usually you must be working flat out, with miserable people or what have you for that to build up over time. If you can afford to take time off you should. If you're constantly working late, stop. Sometimes unreasonable demands from employers/customers whatever can make life really difficult. You need to make you're life more liveable, or if possible change track altogether. If people are pushing you too far and to your limits, you need to get them to back off and be quite assertive about this. I used to let people run me ragged, but not any more. It's not always easy to get the balance right, but good luck. Can't say more, not knowing your situation exactly.