Dub, I understand your pain. It is valid. However, I wouldn't even waste my time on wondering about how they feel or think. It is a fool's errand. Trust me...don't bother. Just live and learn. I am not dismissing here at all. I understand all too well what you are going through. However, at the same time you have to come to a point where you realize...I deserve better. I want better. I will expect better. I will do better!
It is all about changing your perspective. If someone does you bogus regardless if they are disordered or not you need to steel your heart toward them and move on. Become indifferent because in truth the pain, anguish, frustration, etc isn't worth it. I am pretty sure you know this. We all have to process and grieve in our own way and on our own timelines. Just be kind to yourself and don't try to understand what doesn't make sense.
Getting overlapped stings. However, also realize that the person who overlapped you is a coward and they will screw over the replacement too...be rest assured of it. The poor sucker has no idea the sh*t storm they are in for. The best thing you can do...disengage and don't give them an inch moving forward. You were disrespected...there is no coming back after that. Remember...respect trumps all! Keep your head up and look forward to kicking

$$ this bright new year and dispose of the trash of the past. Create a new and improved YOU.
Cheers and best wishes!
-SC-