Need a quick explanation on LP please..

Ok, so I was silver 1 and now back to silver 2. Before I won my series the first time I made it to my series 6 times and had a terrible streak of leavers and intentional trolls during everyone of my series games.

Before I make it to my series for the 7th time I'm gaining 24-28 LP per win and only losing 13-16. I win my series get to silver 1. Win 2 off the bat and then lost 2 right after that.When I won I only gained 16 each which I thought was odd considering the amount I was gaining in silver 2 and when I loss it was a huge hit of 20 LP. So annoyed I didn't play ranked for a day. Came back lost 1 at 0 Lp and instantly demoted back to silver 2 on my first 0 LP loss.

So I'm extremely annoyed and now when I win a silver 2 game I only gain 16 and lose 20 every time.

Why did my gains drop and my losses shoot up happen so drastically with so little games between on top of me deranking the first loss I have at 0 LP?...