Whats with the ranked LP gains?

Your MMR must be lower than the average MMR of your current division. If you were S5 last year and you got demoted to B1, it means that your MMR has dropped to one of a B5 player. Work your way back up and try to win many matches in a row. I know it sounds stupid and exagerated but that's the only way of going up. If you want some advice, I suggest playing one champion and get out of Bronze with him/her. That's what I did and it worked fine with me. Also you can duoQ with someone you trust and you can carry all games with only you two. There are many possibilities, but it is you that has to choose one to go back in Silver. Good luck and have fun! :)