Too sick for this, help for unneeded drama

WARNING! If you hate drama and pettiness steer clear. Assholes and trolls are welcome but not needed. Unfortunately for me, I have been experiencing a steep decline in my health due to well, uterine cancer. So as much as I would love to focus on something else at the moment, my life pretty much consists of surgeries to keep me busy. Now to get started... I was in a 2 year relationship with my ex (let's call him A) who is an abusive narcissist who constantly cheated. Our relationship ended in 2012 with me recovering from surgery and miscarried. His next relationship, let's call her K, began during the end of ours ( I find out later). She became obsessed with me and started changing everything to look more like me. Petty to say I know. I had red hair then and she dyed hers. I changed back to black and then she did the same. She changed her clothing to match what he told her I wear. She hated me and I was nothing but nice to her. When he tried cheating on her with me, I let her know right away. It wasn't until she left him finally that we became friends. She was finally able to be herself. Flash forward to now, his new relationship let's call her D is doing the same thing only I literally have no part of this. I am unfortunately in the middle of the war between K and D. Our ex started dating someone who worked next door to K. K is a Fred Meyers manager and D is a Hair stylist at the salon next door. Let it be known that A and I are 23 and D is 19. I know, I am too old to be dealing with highschool bullshit. But like I said, the only other things I have to think about are my health while all of this is going on. Alright so K informs me of things that D is doing to either her or me. http://imgur.com/a/zu2XV A couple weeks ago my ferret died. My ex A had her as I was not able to keep her at my place. My name is on everything including her adoption papers but, when we split he kept her. I missed her a lot and he didn't allow me to see her. Well K had D on her fb and seen that D was trying to change my ferret's name and lied about where the name came from, claiming ownership over her. This prompted me to write to her as you can see from the pictures. Right after this she started "single white female-ing" me. Dyed her hair silver, got a tattoo that I had been planning for several years which is all over my fb. Things like that. K says that she has been saying I stalk her and copy her and all that bs even though our ex has apparently confronted her about it as well. Although that doesn't mean much considering how psycho he is. I would really love for all of this to finally be over. I want peace and I don't understand why this keeps happening. It doesn't help that I am too curious for motive to actually move on. Thus, my posting here. Thoughts and opinions are much needed. If you want to judge me, that is fine. I understand how the internet works. I just want some semblance of why. Thank you for taking time to read this.