Electrical issue

I've got a 2000 Tundra. Friday everything wa fine. Got up to take the trash off and was greeted with a high pitched sound (sounds like the alarm that you get if you try to lock a door before it’s clised). Battery was completely drained to where it wouldn’t even jump.

Recharged the battery and hooked it back up and the same thing happened. Pulled fuses until I found the problem. It’s the fuse that controls dome light, radio and keyless entry. Brand new battery and alternator as of 6 months ago. Frame was also replaced 6 weeks. I’m at loss. Any ideas

 

Are you sure your dome lights are turned off when the doors are closed, check the switch. I've had a dead battery that way.