Here's what I think happened to your lipo :
1- 11.1 15c getting hot fast : the discharge rate of you're battery is too low for your gun.
2- "I get is a click that usually happens when I am low on juice" : If this happens you discharge the battery way too much.
3- Firefox batteries are just ok, try a better brand.
Conclusion that battery is dead, discharge it properly and send it for recycling.
What you need to do : Get a proper battery with at least 20c discharge rate (higher is even better). Get a good balance charger. Always balance charge the battery and use the storage mode on the charger after each game. This will allow you to keep the battery working for a long time.