Hello, ananda!
It's not self-pity...(I know I can't help it when I'm in a foul mood). If you need to vent, vent.
Any time I feel good, I try to enjoy it because I know it won't last much longer. Who knows? In a couple of hours I might feel like crap. One word or one stray thought is enough to do it. I feel like I get mood swings all the time--some are bad, but usually it's manageable.