LP GAINS IN DIAMOND

Does anybody understand why my LP gains are so terrible with my 55% win rate and enough games for that to matter. My MMR isn't terrible either as you can see because almost all players in my games are same ELO as me such as my last game where everyone was diamond 4. I just went on a 4 game winning streak earning 16 LP per game and get my first loss and lose 17 truly don't understand this system.