Always paired with bad teammates, and against good teammates in casual games. Would like some advice

I am not a ranked player, I just play for fun. But why am I always paired with teammates who feed. Just the other day, I got paired with an Olaf who went 1/22, and a Shyvana who went 3/9 and ran into team fights alone like a mad man. For those of you who say I should just learn how to carry, I try my hardest. I would call myself a descent player, but it's hard to do my best when the majority of the people on the opposing team are fed. My win rate went down by 50% ( from 75%) because this season I am being paired up with horrible teammates. I am almost always at a positive K.D. ratio and when we win, it's usually because I carry hard. (Ex. 20/2) Call me a bad player, I don't mind, but is there any way I can get better? I feel it is my responsibility to carry because I know I can't fix this bad team pairing, but the thing is, how do I get good with teammates who feed? I need some advice.

(It is also worth noting I main top lane w/ Akali and Gnar being my mains,) (I also second support with Nami and Bard )

It is really difficult to carry as support, or as an assassin if my team doesn't know how to team fight with one. Any advice? I am not open to switching lanes because I don't like any other one (Jungle is an exception)

Edit: For those of you who say to carry; It should not be my job to carry. It is my job to win lane and roam. Just because other people can't, doesn't mean I should have to carry.