I tried to merge this account with my previous, unregistered one. So I clicked on the link to recover my account and entered my email address. But I haven't received an email yet. I tried to register that account a few days ago, but that didn't work either. It seems that I just don't get any emails by stackoverflow. My spam folder is empty, I checked that. What can be the reason for this?
Two emails were sent to you... Regarding your newer, registered account. Unfortunately when you have two accounts with the same email, using the recovery tool tends to be a bit of a crap-shoot.
I've merged your accounts manually, so you should be set now.