MMR question

So recently I have been doing very well in ranked, winning my past 13 out of 16 games. I am making my way back to Silver after being demoted to bronze after S6 Placements. However, regardless of my success in ranked so far, my MMR is still lower than the average of my rank. Last season whenever I had similar winning streaks, my MMR would be much higher than the average for my rank. I am just curious on why this is, or if OP.gg and other sites are still working out issues in season 6. I want to figure out why I am still loosing more than I gain. Here are some links for some more insights:

http://na.op.gg/summoner/userName=Kettelcorn

http://www.lolking.net/summoner/na/66093938

Thats for the feedback in advance!