I think everyone has problem with it one time or another. I made myself these rules:

If I lose 10% BR, I'll take a at least one hour break. Maybe go read some forums or check poker tracker on all my losing hands and analyze them. If it's just a bad beat, just let it be. but take a break.

If I lose 20% BR, I'll take the rest of the day off. Tell myself repeatedly "I WILL NOT PLAY until I sleep and wake up again". Read some more, watch some videos, learn. When I lose a lot I get motivated to get better. It gets really tempting to go back on and "win it back", but just have to realize, the win it back mentality is the worst. I ask myself, what if I lose even more? Again, check poker tracker on all the major losing hand, ask yourself, could it have been played better?

If I lose my stack at a table, I leave that table. Its so easy to get into the mentality "He made such a bad call and beat me. He's such a fish I bet I can suck more value from him. I'm gonna get it back from him." It's the worst when you try to beat someone or get back at someone, instead of winning money.

Also, find at least another hobby or two. It's unhealthy for a person to have poker as their only thing and devote his life to it due to the high variance nature of the game (most of the time I wonder how the pros do it). so when you are playing badly, just stop, and go do other things that are interesting. If you have nothing to occupy your life other than poker, its much easier to go on tilt.