I lose more LP than I gain?

Recently I have been playing Ranked, and winning and losing a fair bit of games. After I hit Gold II, my MMR started to drop significantly. I was playing mainly Solo, and even after continuously winning my MMR continued to go down. I used to be gaining about 19-21 LP, and Losing 15-16, but now I lose 19lp and gain 16lp. Is this normal? Should I be losing 3 more than I gain when I continue to win?