haha no worries.. same usual speed for me too.
I was going to suggest Firefox but you like IE well enough so I'll not go through the Firefox praise! I didn't ever want to change either but I do adore Firefox now - I like the tabbed browsing and the ad blocking but I guess IE is catching up on that too.
I wondered if there was perhaps something in that clunky "hidden" directory of temp files that IE uses and doesn't automatically empty itself when you tell it to dump the cache. If there is and it's come from a site you visit at home and at work that could have explained the dual issue.