I add my voice to those pointing out that guitar size matters. I had a guitar that was way too big for me. My new one, much smaller/thinner/lighter though still a dreadnought, makes a lot of difference!
Also, I have similar struggles with Dm. That sinking feeling when it comes up... but I shall prevail, as shall you.
Play on.
"I got this guitar and I learned how to make it talk."