Ranked Flex Matchmaking: I'm Bronze but I have to go against Platinum and Diamonds every game?

I don't understand the matchmaking system. I've had multiple games where it was me and 2-4 Bronze 5s against 2-4 Plat/Diamond players. Is there a reason the high ranked players are always on the same team? This happens whether I duo or solo queue. At best the match will be relatively even, and it's a fun, close games, win or lose. Usually, though, one of my lanes (including mine) gets stomped because they are going against someone 2+ leagues higher than them. I don't mind playing against people a lot better than me in normal if I'm practicing to get better, but having to rank up against people far higher than me is sort of ridiculous. And how is beating me worth only 4 less LP?

On another note, I was put in series, lost ONE game, and was notified that I have failed to succeed in my series. Is this normal?

Anyway, thank you to whoever took the time to read the whining. Good luck out there.