I'm on a constant losing streak, am i just bad or do i just keep getting matched against better play

I've been on a near constant loosing streak since about the end of last ranked season. I don't think i'm bad though I do admit some of my games I just do terribly, but I seem to lose more either because the enemy team was horribly difficult to play against (yesterday I played against a vlad, janna, cait, and elise in the same game which meant no one could engage) or someone on my team just did terribly and/or refused to help the team (like a nasus who refused to help us team fight and kept getting caught out split pushing) I main jungle and so it's hard to win every lane for my team. Am I just bad because I keep losing, or is there something that i'm doing wrong? Is there some sort of secret i'm missing that allows me to carry for my team? I want to be able to actually raise my rank, not just barely stay where I am.

P.S. I'm trying to get better and i'm trying to learn how to carry. Don't just say carry harder without any advice, it doesn't add anything to the conversation, it just makes you look like a jerk.