I'm very frustrated by the way my games end

I'm stuck in Iron(yes, I suck) and I almost always get a lead early. What happens next, is the mid-game. We never get any towers. Why? Because my teammates are running around the map farming and mostly trying to kill people. The result: Everyone has over 5 deaths. Sometimes, I follow them into trying to kill people by fighting 3v5s and end up dying as well, but even if I don't, there's never a proper team-fight as someone on my team is always dead. For some reason, the enemy team's macro always seem so good. They're grouping, going for baron, baiting with it, getting vision control, splitpushing... I have no idea what to do. Do I need to change the way I play, or play another champion... I'm trying to tell them to play for objectives, but the only objectives they play for is the Dragon, and they always try too hard to contest it. Shotcalling seems so useless to me, as at maximum, only one or two people listen. A month ago, it was so much easier, as my teammates would actually listen to what I was saying... Now everything seems hopeless

[sg-shisa]

Losing so much lp...