I just can't win ranked games anymore.

I don't even know what's going on. Ever since the ADC changes went live I simply can't win ranked games. No matter how far ahead we are we always end up losing. Was in promos for platinum 1 before the patch, right now I'm in platinum 4. Not exactly sure what I'm doing wrong since I'm familiar with the meta picks and builds and use them myself and I'm hardly ever a burden to carry. Any tips on how not to suck so much?