I went 7/10 in placements. Where I was, I had 70% winrate.

You won 7/10 of your placements against bronze 4 and 5 players. you ended last season in bronze 3. What were you expecting to happen?

welcome to ranked, everyone gets placed lower than they deserved. its not just you.

but ask yourself were u silver or bronze last year? did u get carried in those 7 games you won?

Because you were Bronze 3 last season.

Its based on prior MMR, not winrate.

Your wins/losses in placements only tweak your prior MMR a little.

wow 70% winrate you must be put atleast in platinum

go on OP.GG to look at you'r MMR

http://na.op.gg/summoner/userName=hrd2h1t

thats your MMR