I have a more than positive winrate in ranked, yet i get 17 Lp and lose 22 Lp, even when i was on a 4 win streak. Each one netted me 16-17 LP but then i finally lost and it was 24 LP... I failed my promos and now i am at 64 LP, thats 2-3 back to back wins i need to play to get back up to my promos...
That means that riot thinks you should be at a lower bracket.
it usually has to do with a lower than average mmr for your league. you could check your mmr at opgg.
My suggestion though is a little different. Stop worrying about LP LP is like Pyrite. looks valuable but is worthless. your mmr determines your climb and your mmr will only rise if you become a better player. If your winrate is positive thats a good start. keep it up, improve your own gameplay and you'll climb in no time
