Did you open it from Google? You may have a Google virus
I’ve also experienced a strange .de at the end of a bookmarked fiverr URL
Only once though.
Anytime you are concerned about being re-directed you should close that window and/or tab. Once you get back on the official Fiverr website you should bookmark it. You also may have a re-direct virus so I would suggest do a complete virus sweep/scan of your computer