I actually got it all fixed now. Somehow my email account had a glitch where my mail was being forwarded to a different account. I set that up once while I was having trouble with Yahoo a long time ago, but turned it off once the problem was resolved. Any way, there was some kind of glitch and when I checked that other account, all the mail I wasn't getting was there.
I knew I could register a new account with Yahoo, but what I wanted to do was change my proflle here so my topic reply notifications and such would go to a different email address, without my having to completely re-register here, if that makes sense.