Electrical problem??

[z28tito]

I have a 99 Z28 and yersterday as I was driving to work I noticed that the battery guage was steadily going down. After work I was driving home and it continued the same trend and the battery guage went all the way down to nothing. The car still ran but nothing electrical worked and the car would not go faster than about 45mph. I was just glad to make it back home. I'm thinking it might be the alternator/wiring. Anybody had a similar problem or have any ideas? Originally though it might be the battery but it tested out fine.

[GOT1GOAT]

First off, Welcome. Second, Ask your question in the electrical section to get better info.