stop loss - theory and praxis

I know the common advice is to play when the games are good and leave when they're not, and not to end sessions prematurely just because you're loosing. But I know for a fact that I don't play as well when I'm loosing. Maybe some day I'll be consistent enough, but I'm not right now. Loosing 10BI @ 50NL is pretty huge for me considering that I was playing 5NL just 3 months ago.
Swings are bad for my game. I don't feel confident... I don't even want to sit down anymore. What I think I should do is move down once a downswing gets uncomfortable. I think I might have waited too long here. I actually moved down to 10NL for a couple of hands with some 25NL, donkstakes donkaments and sng's, until I moved up again.
I'm thinking at around -5BI in consecutive losses, I should just move down one level, and wait until I'm up at least 2BI there before I move back up again. Moving down once more from there if the swing continues would be overkill and definitely hurt my profits in the long run, but cutting the stakes in half for a while doesn't seems so bad... It's not like one level down is going to cut my EV in half either.
I'm aware that that isn't a system that is going to be +EV just by the nature of it, but I think it's good for my mental health....

So... Idk... just random thoughts without much merrit, but I feel like I have to do something there.

I think stop losses are a good thing. For me, if I lose 5% of my roll in any one day, it's time to quit for that day. Also, I move up a level when I get 30 buy-ins for that level and move DOWN when I drop to 20 buy-ins for that level. That kind of bankroll management takes care of all the mental hurdles, bad play, and variance that poker players have to endure. On the other hand, just because you're losing or just because you THINK you're in a downswing is not good enough reason to not play or move down in my opinion. You don't want to go too far the other direction and start running scared every time something bad happens.