Nope, didn't read it until you just mentioned it. I think it could be true and I also know that mental health can surely cause people to grow apart.
In fact, since you asked, the situation with my best friend for many years happened after I gave birth to my first daughter. I was not in a good place being under the spell of a toxic psycho as the baby daddy and I could not even get myself to appear at her wedding because I was heavily post partum depressed.
My so called supporting partner (sarcasm lol) made sure to make the bridge between us even bigger and put me in a bad spot. A few years later, I reached out to her and we both agreed it was all under the spell of bad hormones and in a toxic relationship, no grudges and it seemed we'd continue where we left off for a bit.. until it didn't. Our lives had grown apart too much but at least it gave me some closure, which was good.
I wish you the same. We can all be dickheads and make mistakes, if we own up to them and learn from them, we should deserve a second chance if the friendship was worthy.
I know you're not that bad, and even if so, everyone messes up, I sure know I did many many times. In the end we live and learn ..
Keep trying if you feel there's a chance to get some closure, but surely don't let this overtake you in a bad way because then it's clearly not worth it or just not the right time.
<3