Is it possible to merge two users?
Yes, this is on TWN, where we are not in the WMF instance, so we can try merging your two accounts.
We don't have any user merge extension here and there's no plan to install it, so I'd just decline this request. User:Sveinki has less than 500 edits; User:Sveinn í Felli is older, has an email address and was used recently. If you just stop using "Sveinki", you'll be fine. I can block and/or rename the account you don't want to use and you can place a redirect from one username from the other. We can also recover the password of either account if you lost it and the email address doesn't work.