First off, not sure why you posted in tune submissions, but it must be because this problem has you totally rattled
I'm no expert, but here's something to start with: take the amp to another location (friend's house, work, etc.) and try it there. This will tell you if the problem is your amp or your house's electrical wiring. Also, try another guitar both at your home and at another location, because sometimes it's the pick-ups or something in the guitar. This way, you can at least narrow it down and make sure it's the amp. I had a similar problem and it was the reastat (sp?) lighting in my house and the single coil pickups. Hope this is some help.
"The only funeral you should ever try to interrupt is your own, and that should be a full-time job." -Kinky Friedman