Please help I dont know what im doing wrong and on massive loss streak

Okay, so Im not whinning about teamates but I really want to know what I need to do to help my team win a game, I main vi and jungle alot and never feed, I always gank ALOT and help push back or kill the people theyre laning with like 2 or 3 times each lane, I try and gank at every oppurtunity and solo dragon and farm and hold towers when needed but it seems like my teamates always lose their lane hard I always go like average around 10/5/7 sometimes I break even and sometimes I get loads of kills and help push turrets alot, but we still lose. It usualy seems like our adc feeds hard and or jsut is countered hard.

So I tried changing things up a bitand used miss fortune since shes f2p and I RARELY use adc and have never before used miss fortune and I played 2 bot matchs and then 2 player matchs with her and the first player match my support stole all my kills and farm but we still carried, the second game we completely slaughtered the enemy team in team fights and me and my support were carrying and making big plays and pushing towers and we were about to win after getting baron the 2nd time and of course just my luck our warwick doestn wanna group to destroy nexus and we lost. Even though our support stole almost all the farm and kills I went something like 28/8/10 and he went 22/6/9 and WE STILL LOST SOMEHOW, now I usualy never lose my lanes hard ever unless its a champ im new with, but Their team even ganked us like 4times and me and adc with half health managed to kill all 3, the jungler adc and support every time. I just dont know what to do guys :C we even roamed and pushed all of their turrets for them and we still lost. :c I always go for objectives and try not to die or ult needlessly and I even 1v5ed their team and stopped them from destroying our nexus while everyone was saying gg. I just dont know what to do :C