Before this session had you had a few winning sessions on the books? I ask because sometimes you can go on a “winners tilt”. The second question is one of your mental state. Because you knew it was a loose game did you feel that you could crush it? It sounds like the first hand really got you off balance and made the pace for the rest of the night.
Whenever my state of mind becomes impaired I read “Ace on the River” by Barry Greenstein. It’s a good way for me to recenter my focus and remind myself there are going to be nights where you can do everything right, and still lose. It’s just the variance of the game. You can either fight against it, or embrace it.
I tend to Embrace the Variance. There will always be another game, another pot, and another day. Just play your game, learn from your mistakes, and keep swimming.