It seems to be just a glitch, don't worry about it. I just jumped down from level 20 to level 6 as well

LOL yeah it's happening alot I have gone down from 20 to 6 but GS have said that every action is stored so as soon as the glitch is worked out you should go back to where you were including whats added today.

lol i was level like 25 or something i thought at start it's 26 and now i realize it's 6 LOL