Stop using the computer you normally use. It's likely your computer has been rooted / compremised in some way; continuing to use it until totally clean (likely requiring reformatting and reinstalling everything) will likely make matters worse.
From another computer (preferribly one that's connected via cable / dsl; not wireless - disable wifi to be extra safe) that's been scanned for viruses, spyware, etc beforehand change your passwords on all the accounts you have accessed in the past few months from your computer; domain accounts, email accounts, bank account, etc.
Contact the registrars of the domains affected; it appears you have already done that.
Be persistent, but also understand that it may take some time for the domains to be recovered depending on how they were taken, etc.
If you used whois privacy, that could make recovery much harder ... and possibly, though the chance is small, you could lose some domains; whois privacy, in my experience, is an open invitation for domain theft.
Ron
