Does playing the same role set you up for failure?

So, I feel like there might be something going on when you play the same role SO many times. When I play support for up to 5-6 games, I'll start winning, but then I notice my teams get worse and worse each game, until I start losing games. It happens any other role I play, be it ADC or Mid.

BUT if I stop playing support, and switch to like ADC or Mid randomly, my teams are significantly better. Is there something Riot has done to affect roles that stops you from "maining" one specific role your whole gaming career?