I just got into kegging and at first thought it was the best idea ever! I checked all my kegs for leaks like I was supposed to, was gifted a brand new regulator, tubing, and a CO2 canister (a small one but still). Got everything hooked up and running like it was supposed to be and dispensing perfectly. A couple of weeks later with the same beer, about half gone, my CO2 canister is completely empty and the beer is barely being pushed out. It's still under some pressure because it is being slightly pushed...and when I pull the relief valve there's an escape of gas, but how am I completely out of CO2 already? Am I doing something wrong?!