I'm not a shrink, but I can offer that when I've dwelled on losses, it's usually because there were other areas of my life that I wasn't feeling happy about, be they relationships, finances, employment, whatever. I'd throw a pity party about the money, but it wasn't really about the money...it was largely because I'd use my poker winnings as a psychological bandaid to compensate for other aspects of my life I was too cowardly to face head-on. e.g. "Yeah, I'm stuck in a crappy relationship, but who cares: I made $15K this week!"...take away that $15K and all I'm left with is a crappy relationship...so almost as an ego defense mechanism, I'd lament the lost $15K so I didn't have to face the fact that I was too cowardly to address the real problems in my life.
I don't know you, OP, but look at the other things you do or do not have going for you...if you were in an awesome relationship, with loving friends and family, feeling adequately challenged by your employment, and in a state of spiritual fulfillment, I doubt you'd be grieving the loss of a piggy bank, even a substantial one. p.s. if you can tell me how to get all of those things, i'd appreciate it.