How to be ADC Main in Low Elo?

A bit of a ramble for the most part. Skip to the bold text if you want to just get to the point.

So I finally decided to test the waters of ranked play after being content with my normal games. I'm not really an aggressive type but I do appreciate competition, and ranked seemed like a fun gauge of how well I was doing.

In my 10 placement games, I went 2-8 and was placed in Bronze 1. I know I'm far from the best player, but I think I know the ADC game pretty well. I was honestly hoping to be placed in a Silver division, because my friend who is not really good at ADC somehow got a Silver placement by feeding on Varus...

Now, I know it sounds arrogant, deflective, and maybe even a little irresponsible to say, but I've found that I can't really be successful in the bot lane with the supports I usually get. I know I'll probably be told I'm just another uptight, conceited carry but that's not true. I enjoy playing all lanes and I appreciate the support role. I don't even mind if my supports get kills because they're usually doing half the work anyway. (Sometimes even more of the work when I'm having an off-day.)

However, when you get a Sona who goes to ward a bush that you've pinged several times to back off because there was a Zyra and a Cait in there... or when Thresh calls you a bad player just because you ran when Quinn blinded you and you were expecting a Lux snare/ult combo any second now - therefore you blew an "ez kill" and he will be going top lane and not be coming bot lane again because "you do nothing"... or when Leona doesn't know what a ward is...

I'm sorry to say that I feel like I can't actually carry as the carry at my rank. I had 50LP about 12 hours ago and now I have exactly 0. By the time I'm even relevant and can damage champs, the game is already extremely tilted in one team's favor because another lane got ganked hard or someone fed. Not saying I've never fed before, but that's just the dynamics of the game. And the reason I feel like I can't make a difference is because of my supports. Not only does my LP rely on how well 4 other people do on my team, but my personal MMR relies on how well the other one person in my lane performs.

And getting flamed by a support is the most interesting thing. I'd always heard about how bad supports have it and that ADCs treat them like crap. But I have been called by various supports "bad Ashe", "this Caitlyn", "trash Sivir" because I was only 1/1/3 at 15 minutes in.

No, I cannot go in for the kill you set up next to the river when I'm busy warding off winions.

So I guess my question is, how can you carry as a carry in low elo when you have to share a lane with someone who may or may not be that good? I want to improve my skills and I don't want to blame anyone else for my own mistakes, but there is only so much you can do in a mutually reliant relationship.