Are you having a better day today,
seh? I know how tough those bad days are.
You're right, it will take time to come to terms with everything, heal, and detach. It does get better. Eventually there are more good days than bad days, and the bad days continue to decrease. You've been hurt badly, you're grieving - it takes time.
It just kills me that she moved on like I was nothing. It made me feel disposable.
I felt disposable when my ex left me and moved on like nothing had happened. It's so painful to feel discarded by and meaningless to a person you love dearly.
Learning about BPD really helped me get over this flawed thinking. Realizing that my ex was more motivated by his overwhelming emotions, fears, and unfulfilled needs than by anything I did, helped me realize that his treatment of me didn't mean that I was 'nothing' to him.
I just can't wrap my head around how someone could supposedly love you so very much and then BAM! Drop you like a hot coal. (I know it's the BPD) I know normal healthy people don't act like that.
No, healthy people don't act like that. The good news is that, by becoming healthy yourself, you will naturally draw healthy people into your life.

Have you looked at the lessons on BPD behaviors here yet? If not, you might find them helpful in learning more about BPD, and understanding what happened in your relationship.
[LESSON] BPD Behaviors