We never did hear who your email provider is???? Intermittent problems that affect email for a half day or so occasionally happen- servers go down, glitches, etc. Certainly if it went on for two days that would be grounds for looking into it further, but unless you change settings then I would start with your email provider and see if they are having issues with servers, etc.
I know with .Mac I can check the web site and it will show some of the outtages, but often times I will have issues when they don't show up for most .Mac members and never shows up on the .Mac website where they list the status of servers, etc.
Hope it stay up and running for you! Let us know who your email provider is and how long it was out of service- that helps others that surf these fourums!!