Thanks for the detailed answer(s) :)
You are certainly very bad.
The ranking algorithm is very accurate.
In fact, at your level, if you were playing at pro level, you would literally win 99% of your current games. [from other comment]
Its good to hear these, because if the ranking is accurate and I'm bad, and its possible to make this big of a difference in one game then I can improve! I feared that skill levels in dota doesn't really vary, so thanks for pointing these out. But I love to play competitively, push myself to a limit, and figure things out (just like in starcraft).
I try to use the ping / chat wheel as much as I can. I love that feature, has nearly everything I need. I noticed that there is a setting to ignore messages from everybody except friends, and its the default so usually I don't really chat, only reply if somebody is saying something. I'm sure typing messages is superior to using chat wheel only, but not sure how much