In college in the theatre department our slogan was - "If you're thinking about quitting once a month, you're fine - if you're thinking about quitting once a day, get out". Now, that was in regards to being a theatre major, but the basic sense is the same. If you spend more time wishing that you were out of theatre, then I'd say its time to leave. If not, it might just be time for a good vacation or a new position. I was really tired of working with actors, and have ended up at a road house - I'm still in theatre, and my title is still a SM, but I'm enjoying the break from the day to day dealing with performers. Yeah, they come through with the tour, but I don't have to deal with them.
-Centaura