How to increase LP Gains

Hello, recently I have finished my placements winning 9 out of 10 games. I then went on to win 6 games and lose 3, and I am in gold 3. I have been earning until up to this point, around 27 LP, then for the past 3 games I've gotten 15-19. I was Platinum last season, and I have won lots more games than I have lost. What do I do? Is my MMR just fucked permanently? Do I have to create a new account and waste all the money I spent?