First I should say my therapist has said I have bpd traits and tendencies, and upon further research I can say that I do relate a lot to people with "quiet bpd". So I thought I'd bring my issue up here.

I had someone who was my best friend for the past 6 years. We talked every day about everything, and if I had to classify one person other than my SO as my FP, it would be her.  
She recently stopped talking to me after an argument. I tried reaching our several times to no avail, and according to social media she has basically replaced me with a new best friend. All the plans we had and the inside jokes and the pacts we made are just nothing now. I am 27, I feel silly talking about best friend drama like this but it hurt. It really hurt.

I would cry nightly and ruminate about it constantly, and the only way I really get over break-ups, friend ones or relationship ones, is to basically decide to hate the other person. Unfortunately our friend groups are still very closely intertwined and I really cant afford to outwardly hate her or avoid her etc. It's been a difficult mental adjustment to say the least.

So now I've resorted to trying not to think about it. But even I have noticed that my behavior has... changed. For one, I'm hyper-fixating on my pet dog, a lot. Getting him the best food, a new leash, a new harness, vowing to brush his teeth every night. I blamed this behavior on a recent health incident he had recently, but I feel like it's become more than that. 

Similarly a new obsession with my boyfriend of 4 years. Now I have always loved him but now it's like, when I'm not with him all I do is miss him, think about how great he is and how lucky I am to have him, I have to stop myself from letting my behavior come across like I'm smothering him.

And the thought of losing either my dog or my boyfriend terrifies me to my core. It's like I'm taking the energy I once put into my friendship with my now-ex-bestfriend, and I'm aiming it now at them. And I get so emotional just thinking about them, and how they are the best things in my life and I love them so much, and while I've always loved them, something about now is different, almost like it's at a detriment to myself.

Has anyone had any similar experiences? Any input on this would be very appreciated.