Why did my Live Mail reload EVERY email as new today?

I closed all open programs last night and placed the laptop in hibernate mode. When I turned on the computer this morning , there was a window saying the email couldn't connect to my server (Comcast). I closed the box and opened my email account. It kept loading emails for a while. I now have EVERY email listed in bold and as unread. If I hadn't deleted the email yet, it merely placed a copy of the reloaded email directly above the same exact message that was already there. Now it says I have 2000 new emails. (and I check and read my emails daily) Question #1, why did this happen? #2, Will it happen again tomorrow or when I reopen my email? #3, What can I do to prevent another episode like this? Thanks in advance for your help.