Why am I so inconsistent?

So I've been having issues with climbing the ranked latter this season. I ended last season Gold 4, I didn't play ranked alot, but I was fine with it. I got placed Silver 4 this season, and in one day I climbed back to Gold. However, I can't seem to get out of Gold 5, and I know that people are saying that I belong there, which is probably true. But I think I have potential to be higher, however I seem to be stuck. My problem though, is that I'm super inconsistent. I either play "perfectly", make the right decisions, and blah blah, or I just lose lane hard, die needlessly, do dumb stuff all game, and am just useless. I do agree that tilt is something I struggle with, but I usually know when I'm tilted and I can take a break, I mean when I'm not tilted I either carry hard or just play like one of the people I hate having on my team when we get stomped. I just want to know if there's a mindset some of you have or any tips or anything to maybe help be more consistent?