Instantly Demoted

So here I am, in Gold III. I'm feeling pretty happy and doing pretty well in my games. My MMR is great, and I am gaining 20 LP each game and losing 16 for each loss. Unfortunately, I went on a 2 game losing streak, dropping me to 0 LP. When I lost my 3rd game though, I got instantly demoted to Gold IV. Is this a normal occurrence to be instantly demoted while at 0 LP? Usually there is at least one buffer game, especially when I haven't lost a game at 0 LP in Gold III yet. I'll be able to climb back pretty easily but still, this seems odd to me.