Battery drain

Thank you for this post I had a CD stuck in my player drained the battery.

I installed a Boss 722CA car stereo into my 2001 Chevy Tracker, but made sure to disconnect the ground terminal of my car's battery before I started the installation.
I connected the ground terminal back to the battery when I thought I was done, but the radio wouldn't turn on; so I disconnected the terminal again to troubleshoot.
It turned out I'd forgotten a couple of wires.
When I fixed the wiring, I connected the ground terminal again, tightly, and the radio worked great.

However, I immediately noticed that my car was having a little bit of trouble turning on (it normally doesn't). And my electric windows were going up really slowly, too.
The next morning, the car wouldn't turn on; it just repeated several clicking sounds. The air conditioning, dome lights, windows, and wipers all worked; though very weakly (much weaker than normal), and eventually stopped working after a while, too.

Gave my car a jump start and it turned on. Left it running a while, then turned it off and waited until next morning to see if the battery would be drained again.
Next morning, yet again, my car did not start.

I really don't know what's wrong, especially since the wiring has been checked and rechecked, but all the wires are correctly paired, joined, taped, and connected.

Fluctuating power, then brief complete power outage but it returns momentarily. Have replaced battery twice, alternator once. When it completely stops the battery is completely drained. Battery is only two months old. Had a new battery in it before this and had this battery checked at Advance Auto and there was nothing wrong with it. I wonder if a short in the wiring be draining the battery or whether this is a fuel pump problem. This problem has happened three times. First time, cleaning the posts helped for awhile after battery was charged fully. The second time, battery and alternator replaced.