How come i cant win?

Hey guys, i dunno whats happening to me i was in plat 1 and almost diamond 5 but it seems like every game since then i just cannot catch a break. It just seems like the other team always has so much more threats. In my eyes its just usually me vs there whole team. I dropped down all the way to plat 4 When anaylizing my games im losing games were i am 18/7 and 17/7. I dont no what to do my teams scores are usually all 1-6 across the board. You can look up my games LaraqueObama in NA. What the hell am i doing wrong?? I try to help my team so much but it feels like they never can do anything.