Yikes! Think I have an issue with electrical...

Here's the short story. Upstairs bathroom has a gfci with one receptacle and one switch. Wife says lights in bathroom have been acting weird, and today the outlet in the gfci won't work. I opened box, everything looked neat, no stray wires but then I noticed a black wire not attached to anything (or touching anything) and a little piece of copper wire still under one of the screws. Must have broken, I reconnected it expecting that to solve problem. Nothing.
So I think maybe its the gfci. Go to HD, get a new one. I tried connecting it like the instructions but it wouldn't work. I had taken pictures of the old wiring before starting, and so I wired it the same way. Now the gfci shows the solid green light. But...nothing works when plugged into it. And now the overhead bathroom light which has a separate switch doesn't work. And there's no power in my bedroom, and we have an old home alarm with the power light blinking red. I'm guessing it has no power either, hence the blinking. I checked the circuit breakers 50 times - they're all on. What the heck could be going on here? Rest of the house has electricity. I'm guessing my wiring of the gfci couldnt have killed all the others, right? Any advice would be greatly appreciated! I'm also out of work, so if there's anything I can check myself, that would be great. THANKS!
larry