My problem with the MMR system

So last season I ended in Gold 5. Going from Silver 4 to Gold 5 in 4 days was pretty awesome but with a month left in the 2016 season i decided to not try as much as i should.Doing things like picking champions i don't even play in order to get better at them is an example(i'm an Irelia main). Of course i stayed in Gold 5 but i failed to realize the fire i was playing with. My MMR was dropping fast. Before i knew it I was getting 13 lp per win because of my silver 4 MMR. It annoyed me but I was OK with it because the season would soon reset in about a week. Fast forwarding through the shit storm of unranked players vs diamond gods i went through unscathed... or so i thought. I was placed in Silver 3 with silver 5 mmr. I won about 7 games in a row before I realized league has crapped on me because i still was not in promos. Now i assume you understand my problem. If the MMR system thinks i'm a silver 5 player it should have just placed me in silver 5.If it place me in silver 5 i would have an easier time climbing . instead of having to hype myself up to carrying all my games constantly. Which is what I have been doing. It's been a pretty ez climb either way but I'm still annoyed. Right now I am in silver 2 promos with silver 4 mmr wish me luck