I know what you mean and I think that when you get bored, you should do something else. You aren't playing your best poker anymore and the fact that you keep playing even though you are bored, shows that you value profit or a winning session as a measurement of your skill. The reality is that some days you are going to just be losing, no matter how good you are. I read an article that talked about not even looking at your bankroll and just playing poker. I think we get too caught up in trying to make money and lose our enjoyment in the game itself. I think if you return back to your love for the game, then you'll play better.