I'll type a lot because I always appreciate good responses to questions like this when I post them. It's fucking frustrating right? You want to be good at this game but it goes beyond your control. You have four other people you need to carry on your back.
So you won lane. 1 of 5 people on the enemy team is probably demoralized right now, getting frustrated, and probably getting hate on. You need to spread the discord beyond mid lane. Beat him, killed him? This time, don't push tower, pop your blue ward deep in the enemy jung, see it's clear, and go steal wraiths, MAKING SURE TO LEAVE A LITTLE ONE ALIVE, so he knows you were there. See the jungler gank bot? Go take his buff if it's up, or the big krug. YOU ARE NOT MARRIED TO YOUR LANE NOR IS YOUR ONLY OTHER OPTION TO TRY TO GANK BOT AND TOP. Go fuck up that guys jungle man.
Now 2 people are demoralized. Next ping the hell out of ur jungler till he comes to Herald. Once you have Herald, go top and help him shove down his tower, even if yours gets pushed, because you can always go back there and kick that guys ass again. Now 3 people are demoralized. And your team sees you being actively helpful across the map (hopefully).
As for getting ganked, what do you do when you're behind. 0/1/0 0/2/0. You hug your turret and you last hit. Go into custom, and get pro good at last hitting under tower if you aren't already. Now lets say you won lane, so the jungler wants to shut you down. Play like your 0/3/0. Think about it, a 3/0/0 mid laner who refuses to leave his tower, is getting tons of cs, and no one can shut him down because he never plays like hes fed? That's like a giant middle finger right in the enemy junglers face man. Believe me, I jungle, and it's so rare to see this, but when I do, I fuckinghate that guy.
Think of the map as one big lane. You start mid, and you end by diving their fountain as the victory screen comes up, and you go every where in between. As soon as your lane gets pushed beyond the middle point, leave it immediately and go steal his jung, or just get the skuttle. Or go farm your wraiths AS LONG AS YOUR JUNGLER IS COOL WITH IT. Never be idle. Ever. You gotta be like a sniper, you killed your opponent, now change locations before you get counter sniped. The longer a fight lasts the more time the jungler has to get to mid lane and attack you. It's the closest spot on the map from ANYPOINT. If your fight is taking longer than like 5 seconds, then stop. Let him go, let him try to stay in lane and farm with like a quarter health while you have most of yours. Or watch him admit defeeat and B, giving up on CS entirely. You just won, and you didn't need a kill to do it, and you didn't risk getting shut down.
When team fighting starts, you'll have the most CS on both teams, you'll have kills and no deaths, and you WILL CARRY at that point, assuming someone else didn't feed harder than you got fed. There is no formula to winning. Everyone wins, and everyone loses. But if you play conservatively, if you do everything you can to frustrate the enemy, if you farm like a pro and never get shut down, you will win 9 times out of 10.
Incidentally don't look up my profile :P I don't take my own advice. When I fall behind I have a bad habit of trying to force fights and that's like the most terrible thing you can do ever. And When I'm ahead I do what everyone else does, I go go go until I get shut down.