Possible to lose skill in the matter of a week?

I'm an Ekko main whos M7 with like 130k+ mastery points (im a "noob" still) (although my recent games would say differently) and recently i tried playing support, and I really like the position. My winrate is really good with Rakan but sometimes I like to go back and refesh myself with ekko, but it seems that I have lost basically all skill with him whatsoever. Like I now go double-negative with my KD (example: like 5/10 or 3/6) and I constantly get flmaed by my teammates saying Im awful and need to play norms... but this was the exact opposite last week, before i started playing support. Is this a thing? like is it possible to lose a shitload of skill in the matter of a week, or am i just experiencing the losing streak of my big ass winning sreak I had a couple days ago?