What is the difference between love and FP?

So obviously I know the two intersect, my boyfriend of a year broke up with me about 5 days ago. I have been really sad about it don’t get me wrong, I have cried my eyes out and cry a little now. You see my therapist told me she suspects I have BPD 3 days ago, and I think it tracks (going to a psychiatrist next week to start the process of officially getting diagnosed). And looking back a lot of our fights where me having BPD episodes, my ex always felt like he had to walk on eggshells, it sucks things ended this way because we where so happy and meshed so well, but I ultimately respect his decision.

When it first happened I felt like I was dying, a piece of me was taken away, and I just wanted to end it all, I wanted to call him and hold him almost every second. And after he stopped sharing his location with me idk something snapped. I’m still sad, but I have come to the realization he’s not coming back. He was my love, we shared so many good times, and ultimately he was my favorite person. After realizing he was my favorite person, idk it made the grieving a bit easier. Can someone explain to me what is happening because it’s kinda freaking me out. I am so confused, why am I so numb to it all, am I just in shock? Will the sadness and grief come back in a few hours or days?? Today is the first day I am feeling kinda okay, I want to keep feeling okay, I am scared.