Fianc?e got a huge farewell party from her work and it's made me feel crappy

My (29M) fianc?e (28F) just left her job of three years today and was given a farewell by colleagues and kids (she worked in a nursery). They did heaps of cute stuff for her, gifts, chalking the sidewalk, the kids draw for her (she got over 100 drawings) and the staff put together some book thing. She's honestly the most incredible woman I've ever met and I understand why they'll miss her.
It got me thinking about the places I've worked or studied and the people I met during those times and I literally don't talk to any of them. When I left those jobs nobody made any kind of effort of a farewell (I don't like things being about me, I'm talking small gestures like a card or something).
I left the army a little over a year ago, the place where you're told you make friends for life, I haven't spoken to anyone from there almost for as long as I've been out and nor do they check in on me.
I have one childhood friend but even we don't speak too often although I'm equally to blame for that.
I'm struggling to figure out why I feel so down since she showed me pictures and her drawings/gifts. I haven't mentioned it to her because I don't want to make it about me right now seeing as she's upset about leaving. Kinda just trying to figure this out without her; I don't want to worry her or give her something else to feel bad about right now.
Does anyone have any experience with these kinds of feelings and how they overcame them?
Sorry for the incoherent thoughts, I really don't know why I'm feeling this way and I'd love to hear from people who are or have been in a similar situation.
TL;DR
Fianc?e left her job of three years. Everyone clearly will miss her and did nice things for her.
Feel crappy because of how much love my fianc?e got while I've never experienced anything like it before.


Source.