What I mean is, my [21F] best friend [20F] and I are currently drifting apart due to an...incident. I don’t exactly feel comfortable going into detail since this is my first post (although if any of you guys need background info I’ll happily add to the post if necessary). Anyways,  the drifting apart is hurting me mentally and emotionally, and I think it’s safe to say this person is my FP...
I’ve tried to tell my FP why what they did is affecting me so much, but for some reason they’re much more dismissive and distant than they’ve ever been in the 2 years I’ve known them. 
While I very much wish I could have a conversation and patch things up, I don’t have the right to force communication. I can’t really bring myself to even be angry because I love them so much. But their neglect is taking a toll on me. I haven’t been able to stomach solid food for about three weeks and I’m miserable. Not to mention my meds are reacting poorly to my empty stomach. 
I’m sure many of you are used to the black and white thinking. Cutting people off is probably my go to method to find immediate relief from people who hurt me mentally/emotionally. I don’t think it was always this way for me, it just sort of became a coping mechanism. 
My FP has taught me to acknowledge the grey areas in life and was a rock for me on my worst days. The love I have for them is clashing with my instinct to run away. 
Anyways, I’ve decided to write a letter to them and simply left it with their roommate because I didn’t have the nerve to hand it to them personally. The letter basically explains why I’m hurt and my decision to terminate the friendship. While in the moment, delivering the letter relieved some anxiety, I can’t help but cry when I think about how our last interaction is playing out. I hate myself for the way I’m handling this, but I really do think cutting her off will be better for me in the long run. 

TL;DR My best friend and I are drifting apart and they don’t seem interested in repairing our friendship. I’ve decided to cut them off, but I can’t help but feel I missed out on an opportunity to use the “grey area.”