It's sad I dread getting fed early on

There's nothing like going 9/1 by 13 mins but losing because your team turns into cocky little shits thinking they are insanely fed but your teams score is 11 to their 9. Everytime I do this well and no one else on my team does I know we are going to lose. I even told them "guys don't get cocky just stay together and get objectives". 2 minutes later they get caught out. Happens every single time. And hell this shit happens in mid Diamond. I wonder how far up I have to be for this shit not to happen.