Ayo! I recommend you stop and do some research before you potentially hurt yourself. The fact that you said your mod fired and then stopped potentially means you shorted your battery. What battery exactly is it? What's the CDR? Also, you said you "reversed your battery"?! Are you insane?
First, never put a battery in a mech mod reversed. This will 100% result in battery damage, and potentially damage to you. There is NO safety features in a mechanical mod. No circuitry to protect you in the event of user error. It's all up to you to understand how it works, and what exactly is going on when you hit the fire button (ideally, before you hit the fire button).
Second, what resistance does your build ohm out to? In most cases where a battery discharges they'll notice that the mod stops firing for some odd reason (we call it "misfires" -- when you press the button and nothing happens), and then they go to press the button again and kablooey! Bad stuff.
It's possible it's something as simple as your pin coming loose and not making proper contact with your battery, but from the way your first post sounds you should really re-evaluate what you're doing and whether or not you know how to safely operate a mech mod.