Question about LP gains

I have a question about lp gains. I am Gold V and my lp gains are so weird. when I first got to gold v my LP gains were +22 -17. I won a couple of games when i first got to gold v then i had a shitty couple days where i lost like 4 games at 0 lp or something. What im confused about though is im winning again and im getting +18 -18. I just lost a game and got -21 though randomly. that is the most lp i have ever lost. I go on a winning streak and my lp gains go up so little. then i lose 4 games and they drop like crazy.

edit: overall i have 49% winrate and my opgg says I have normal mmr for my rank i feel like i should be at least having better LP gain and loss. what determines LP gain and loss? MMR? the people in the game?