Player in need of some advice.

Hi I'm Aeko. I've been playing since around the end of season 2. In season 3 I trolled around and enjoyed my time in bronze for shits and giggles. After a heated debate with one of my friend's friend, I began to pursue a position in ranked. After many ups and downs, guides and montage watching, I climbed up to plat I in season 3. Season 4 I wanted to get diamond really bad but after a terrible placement match history and tilting. I ended up in Plat V after a decent amount of time.

School then factored in and I began to play less. After many stressful things in my life passed, I began to pick up League again climbing to Plat II. I struggled at this elo so much that I was forced to recalibrate myself and began playing on a smurf to fix out all my issues. As I went through all of the elos, I learned a lot more than I had expected to. I felt a surge of confidence in me and began to play amazingly, so out of my ordinary self in fact, that I managed to hit diamond on my smurf so quickly before my main. I then went back on my main and resuming the same mindset I got that account to diamond as well.

I wanted more however, I thought Diamond V was my skill ceiling but I was determined to learn more, I pushed harder and peaked Diamond III in season 4 and ended up high Diamond IV.

Now onto the season 5, this meta quickly trashed all over my champion pool and I was forced to adapt, I began to learn new champions only to have them quickly nerfed to oblivion, forcing me to return back to old champs. I did decent on my placement matches and worked my way up to where I am now. Middle Plat 1. This terrible terrible place. IMO, its the worst rank to be at, between the toxic "I'm already diamond" players and the people who got boosted by their friends VIA dynamic queue. I quickly grew fustrated in this elo.

Now I barely have fun playing anymore, all games I get are terrible. I get ouplayed, my team gets dominated. I salvage scraps and we lose. I'm not putting blame on anyone here, this isn't about the terrible teams I get. I'm asking for advice because I'm lost, I don't know how or what to do anymore. How do you other players deal with this? How do I get back into my previous mindset where climbing was no issue. Of course,when I first got to Plat I, I too was not innocent of that cocky attitude and demeanor I had. I thought everyone else was below me and that I was going to roflstomp all the other players, I was wrong. Sometimes I carry, sometimes I dont. Other times I choke or throw. Everyone has bad games, but its gotten consitently worse for me, I'm falling into a hole that I can't get out of, and the worst part is that I'm the one putting myself in that hole. Something needs to change, but I don't know where I'm going wrong and what I can do to fix it.

TL:DR. I'm tilting off the rift, losing games consistently and my mindset of League is terrible atm. What's the appropriation behavioral response I should be taking in order to start seeing success in my games?