meh... I wouldn't be. Just because you got "shoved" over to a different website than you originally planned, doesn't mean that there were malicious scripts running on the websites that you actually landed on.
I guess there's a good possibility, but if you do a scan on your hard drives with avast and don't find anything, then I'd say there's a good chance that nothing was "harvested" from you. More of an inconvenience than anything.
Of course, you could always be safe than sorry, so it's up to you if you want to change your 20 passwords or not.