You can win in the short run, but it's not the same as beating the odds. All sessions really add up to one big session. If you're counting cards and betting properly and not getting any heat then you might be able to "beat the odds".

In poker, as any gambling, if you have an edge, you play. If you don't have an edge, for whatever reason, tired, sick, distracted, low skill level, up against players you cannot beat, then you don't play.

Work on your decision making, your game. If you do this long enough you'll have losing streaks long enough to make you think you'll never win again.

The best way to overcome a gambler's mindset is to not have one in the first place.

EDIT: To address other portions of your post, I would set a goal for each day based on your longer term goals. As long as I were confident that I were playing well, I'd continue until I met that goal, regardless of the short term outcomes. If the day ended on a high note, I'd still quit, time to eat, socialize, take a break, get out of the house, live life.