Battery Drain

[sb69chevy]

It seems that ever since I put in a new horn relay and had the horn hooked up to the button, my battery has drained. It will start w/ a jump, but after sitting will not restart. I have unplugged the horn from the relay and turned off the radio, but still no progress. The alternator is working correctly. Do you all think I have a short somewhere, or have I done irreparable damage to the battery over the last month or so w/ drainage? Any other obvious places to check?

P.S. Have taken the battery in twice and they have said it's good, although I'm not too sure on this one.