go to na.op.gg and check your win/loss record league is pretty good at keeping track of the whole shebang over your season career.
the best way to "reset your MMR" is to get your win/loss back to a nice and even 50-50. in your case, you have 54% win rate. regardless of your current ladder standing thats good, that means you're climbing up and proving yourself better than those around you.
unfortunately you cant have a reset back to the starting area of about silver 3, no1 gets to, its an unfortunate truth that we all deal with.
if for some reason you get absolutely trashed in games and have a widely negative win/loss record the best fix is to win a games all at once, or go on a large win spree. if that isn't feasible you have to grind it out and consistently play better than those in your current rank.
this is the thing with riot, they dont care about streaks or performance at all, only your history of wins/losses, they dont care how, just the outcome of the game, win or the lose. if you want to gain more LP than you lose per game, you have to win more than you lose.