Accidents happen. You'll learn from this accident that you need to check the net carefully after every use.
I was moving loaches to a new tank, and pangio are squirmy noodles. I was using one of my extendable nets and had rested it in the water while I moved another loach to the transfer bin.... one of the uncontained loaches wedged himself into the handle of the net and unfortunately offed himself in it in the 10 minutes I was not using the net, just because I left it in the tank.
Learned 2 things that day: don't leave the net in the tank and don't use extendable nets because those extending tubes are hollow.
I'm sorry to hear this accident happened to you, try to learn from it so it doesn't happen again, but try not to beat yourself up about it.