I just can't

I'm sorry I can't climb, it makes no sense, I'm the one with a decent score, decent cs, decent positioning but I can't, no matter what I do, if I play aggressive or just farm, I can't and it sucks because I reached gold and then started loosing non stop. My mmr keeps sinking down even though I'm not the one behind these mistakes, I stay with my team in a safe position and I do the most damage but I can't control the teammate that jumps in for no reason at all, I've had FOUR of those instances today, FOUR, people jump in and I'm left in awe because I can't believe someone would jump 1v5 and I try to fish some kills out of that opportunity but the teammate blows up.

At one point a Jax jumped in on 5 enemies with elder dragon! what am I supposed to do? why is my MMR sinking this bad for something that is NOT my fault? at one point I was earning 28 LP per win IN GOLD 5, I'm currently earning 14 LP per win IN SILVER 2.

I won 3 games in a row during my stay in Silver 1 with crazy good scores, I even felt bad for the people on the enemy team because I was so disgustingly fed, yet I earned 14 LP, reaching up to 98 LP, then, super sinking, loose after loose, some admitedly my fault but definitely not all of them.

I did loose a ton while I was in gold but saying that I'm below silver level is simply hyperbolic, I can't win 27 games (my delta) in a row! it's impossible!!! specially with these teammates! and to top it off, premades! seriously, I'm gonna start finding someone to carry me up because this makes no sense.