I've seen that happen many times, to myself included. I've loved pool all of my adult life, but I find myself not playing nearly as much as i used to. The old adage is, "if you take your hobby and make it your job, you'll have to find another hobby". You can still play, and I don't agree that playing with your customers is always a bad thing. Gambling with them is another matter. Sometimes you're too tired to stay and play after a long day, or maybe you'd like to play some but you know that you have cue work that you've promised that isn't done. It's hard to concentrate on your game when your payroll taxes are due tomorrow. Or maybe someone walks up and asks to have a tip shaped while you're over a ball. Maybe your kitchen is out of lettuce.
It's a million things. I think you're on the right track. Set goals and plan for events to look forward to. I do that too. It forces me to take time to play because I know it's coming up. I'm 26 years in and I wouldn't trade it for anything. I love being around the game, and the pool room and the people. I love sweating the Mosconi cup with my friends, or Derby City, or whatever we have coming up. If I've learned anything, it's that the single worst reason to open a pool room, is because you think you're going to get to play a lot of pool.