You can follow this link to read a helpful guide about managing your bankroll and emotions during fast crash games. I used to have the exact same problem where I would get super confident after a few wins and then lose everything due to rage betting. What helped me was setting a strict limit on my losses before I even open the game. If I lose three rounds in a row - I just close the tab and take a forced break to cool down. Also, try switching to smaller stakes because it takes away a lot of the emotional pressure. Many experienced players actually prefer making smaller bets since it lets you stay in the game longer without risking too much. Just keep your head clear and don't rush.