Someone Help (Advice)

I was able to climb from s3 to high s1 pretty easily, then all of a sudden I completely stop winning games?? I started focusing on my own gameplay, and it improved a bit, but now I'm falling into a routine where for the last five games in a row by 9 minutes my team has had one or two kills to their ten or twelve.

I don't get it. If it is consistently happening then there has to be something I can improve on. I know that. But I just don't get it cause typically by that point I've only died once, if at all.

I play mostly jungle, but the past few horrendous games I have been top. Mostly play tanks, bruisers. Anyone with hard cc or good engage. I know I have too large of a champ pool, but other than that I just don't know what to focus on.