Well, I decided to start by peeking at lolskill.net and then wandering over to na.op.gg to see what those sites had for your stats.
Can I say "ouch"?
First, if I believe the na.op.gg site and their MMR estimator, you should be in bronze 5 rather than 4, and the reason you are seeing more LP lost than gained per game is that the system thinks you are at too high an ELO so it tries to rebalance this through LP gains/losses.
Second, you die 10 or more times far too often in games. Not only does this give the other team more gold they can use to purchase items, but when you are dead you can't provide any help to your team. You need to be much better at knowing when and where to fight.
Third, your champion selection. I see that you play Leona a lot in ranked, which can be good (you are playing just one champ, which should help you improve/play better), but it leaves you much more vulnerable to the play of others (your ADC really determines how the early game goes.) and Leona can't really solo the lane if your ADC is a problem. (DC, Troll, Rage, AFK)
Fourth, more champion selection. You've played 25 different champs in ranked, many only 1 or 2 times and you lose 90% of the time on those 1-2 play champs. I can say only one thing here. "Don't. Just Don't play a champ in ranked unless you know them well.) You need to narrow your champ pool.
So now, I have some suggestions thoughts.
First, don't worry about "trolls" in your games. Its possible to win 4v5 or even 3v5 with good play. (I've been on the losing side of a 3v5 once, the other team just outscaled us when we didn't manage to push any lanes quickly enough.)
Second, play "safer". This doesn't mean to play passive, but more to increase your awareness of the map and what's going on. My friends have told me that when I play bot lane (ADC or support) that they have noticed that I'm incredibly hard to gank. I very rarely over-extend forward so junglers rarely can just dive me and trap me. It does mean that sometimes I don't get kills, but I also don't give up kills. This can prove to be vital mid/late game when the gold win/lost starts to have an impact.
This does mean that wards are your friend. It takes a while to see how this works, but I do recommend that you put a lot of effort into warding. Just last night in one game I was playing support, and was recalling. I watched the minimap and could see a swarm of enemy champs entering the river and heading bot lane towards my ADC who was pushing their inner turret. I warned her and while the enemy team did catch my ADC near their red, our team win the team fight we were able to stage as the ADC led the enemy into the rest of our team. We had wards, they didn't, so we got to fight them where and when we wanted.
Finally, shrink your champ pool for ranked.
Ideally you need 3 for your main role, 3 for a secondary role and 1-2 each for the other roles. (maybe 1-2 more if you have a FoTM champ.)
So for you I see
Support - Leona, Blitz, Morgana
ADC - (3 champs)
MId - (2 champs)
Top - (2 champs)
Jungle - (2 champs)
I didn't name champs because I couldn't get a read on what you liked other that support, and honestly, it won't be often you don't get support if you want it at your elo.
If you work on just a few champions you'll be more able to carry your team in a match, and you'll have more time to do things like watch timers, watch enemy builds, watch the mini-map, ward, call out objectives, call out mia, call out for a push, etc. Those are how you win games.
I've played with bad partners, and still won games. I've been the bad partner at times, and wondered why I was on tilt. But if you work on the little things you get better and the game will come to you. I guess I can use the example of my own play. I mostly play jungle and support, but have ADC as my third position. There I dabble with a couple of champs, but recently Sivir has been the one I play the most. When I first got her I rarely had a KDA above 1.5 and had a few games where I died early and often. (1/14/18 performances don't win games.) Yesterday I ended up playing Sivir 2 times. The first in an ARAM where I went 20/8/39. No other champ on either team had less than 15 deaths. (sadly my team lost once the enemy Sion got tanky.) Shortly after that I ended up in a normal match with a support who had major lag issues and could barely help me in lane. Even with that I managed to get a 4/3/11 KDA and hold the lane while my teams top and mid laners got fed. My team won even though I did not carry. I did enough though.
that's probably the biggest lesson to learn. Don't try to carry your team. Just play smart, play well and keep the objectives in mind (kill the enemy nexus.) Once you start playing better and helping your team win, the LP gains will increase and you can move up.