Our son twists his hair, and went through a period where he was losing his hair. He still does it off and on. I would definitely recommend that you look into counseling/evaluation. Ds turned out not to need treatment (his hair pulling subsided without it), bu we did have him evaluated for general anxiety and got some strategies for dealing with him.
Several things that we tried:
1. Keeping his hair short. It took a while, but when he was finally able to articulate what would help him, one of the things that he said was "if my hair is short, I can't twist it".
2. Having him wear a hat -- that interrupts the movement and can help eliminate it.
3. Watching him to see when he does it and then provide him with other things to fiddle with during those times. Ds does it absent-mindedly while reading and when nervous.
4. Providing him with other sensory toys that he can use with his hands during the times when he normally pulls his hair. A Koosh ball or other fidget toys
(we got a Tangle Jr.)
Things for you:
Freeing your Child from Anxiety is great book for parents of anxious kids.
Schedule time for YOU to recover. You can help your kids if your burnt out!