Sorry to hear that. I really hope that you have so much money that 8k is nothing to you. If that's not the case, then you should take a closer look and be honest to yourself whether there might be some kind of gambling problem in the background because 8k is a lot of money to lose at once.
What stakes were you playing? Did you tilt? There are different approaches when it comes to bankroll management but my own rule has always been 30 buy-ins for each stake. Then it's hard to lose the whole bankroll at once unless you really go on a huge tilt-rampage.
So, in your case I would first make sure that it was only bad session with the wrong BRM, maybe little bit of tilt included, instead of a bigger gambling problem. Then I would start all over again with the correct BRM. Losing 8k also means that you probably have leaks in your game or at least in your mental game so little bit of study wouldn't hurt either. Actually you should always try to study the game more, even the best players in the world do that. Good luck to you in the future, try to stay away from losing 8k at once