860 games in Platinum

So I've recently observed that I'm stuck here in platinum, first I was stuck in platinum 3 and demoting to plat 4 and going back to plat 3, but i've recetly felt in plat 5. I was playing so many games a day until I started winning until promo, fail it, than go back to my LP that I started my day with.

After that, I've demoted even more and started losing more. Started to search strategies, tried them, worked a few games but still losing. I've started to blame myself, than I was sure that my duo partner is the problem so I got rid of him. I was still losing until the point that I'm at right now, playing 2 games a day, 1 win and 1 lose, and being mentally demolished so hard that I don't even try to play another game after a single lose. I just feel like I don't have the energy that I had some time ago. That energy that allowed me to get back up and fight.

I could use any adivce or help.