I ran chkdisk, but I don't know if it found anything. I'm deleting the corrupted files now, which will take a while due to the incorrect file sizes.
Actually, chkdisk did do something. I found a folder called "FOUND.000" and in it were the files that were corrupted. All of them except the text files are fine, and the other files have correct file sizes now. I'll probably just delete those, because I can just save the web pages again. Even so, I think that I will reformat my thumb drive, just in case chkdisk missed something.
Thank you for your help everyone, and I'll be even more careful with my thumb drive in the future.
I know you have this issue technically solved, and it may be, but if I get a drive that badly messed up. I photorec my files I need on it, reformat zero out out the drive, then smash it with a hammer. I do this for multiple reasons
1. I nearly always have a bad drive
2. it always good practice to wipe information off the drive
3. while that format and zeroing is usually enough to wipe information off the disk. Hitting it with a hammer makes me feel better after I spent hours finding and restoring my files.
Again this is my personal experience. As inexpensive as flash drives are it's not worth the risk of loosing valuable data. I had to do this for someone. after hours of trying to "fix" her drive I just ended up photorec'ing it and making a DVD of all her files. The drive was unrecoverable
regarding being more careful with your drive, if you are removing it correctly, there is little you can do. the fact is drives go bad, they have a shelf-life of so many read-writes before it just wears out.