I have solved my problem. Actually two problems.
1) Apparently, my old MobileMe password did not conform to the new iCloud password standards, so my account was diabled. I needed to go to iforgot.apple.com to fix that.
2) However, I had a MobileMe account with a @mac.com or @me.com extension. I also had an Apple ID that was just what was in front of the @mac.com. I needed to use the full email address to reset the password, but I was using just the first part.
On my MacBook, I went to iforgot.apple.com and reset my password using (name)@mac.com. Then I went to Settings, clicked iCloud and logged out, then logged back in with the new password. Email, iCal and iTunes are now all back up and functioning. Hope this helps someone else caught in the iCloud transition, wondering what has gone haywire.