When the ranked reset occurs the highest rank you can be placed in is Platinum 1. This means that all of the Diamond, Master and Challenger players are place into Platinum. This forces the Platinum players into Gold, the Gold players into Silver, and the Silver players into Bronze. Players who finished bronze in season 6 are pretty much guaranteed to get bronze again because everyone starts roughly a tier lower than where they finished last season (or more if you're really high ranked.)
You are exactly where you should be after the reset. What rank you got in your games has no bearing on where you get placed. If you deserve to be gold you'll climb there no problem. I'm already nearly back to where I was last season in flex queue after 18 games because you gain absurd amounts of LP at the beginning of the season.