H2H Ranked

I played for a few hours reached and completed the Champion level to enter top 100 for the Randell Cunningham. As i finished one game to get the points my ranked resetted me back to bronze. I dont understand what happen. How did i get booted back to bronze level after grinding to pass Champion level?? Do i have to grind again to reach top 100 ?? Please help

I'm on Playstation 5..