Sounds like pretty typical depression, maybe some anxiety too. I definitely tend to dwell on past bad experiences when I'm feeling bad.
How frequently does this happen to you? Did it just start recently?
I had been off anti-depressants for a few years and thought I didn't need them anymore, but last winter I noticed I was feeling depressed a lot of the time, and even when not depressed, I just wasn't "happy." I didn't even consider the time of year until spring came and I walked outside on a sunny day and felt like I was waking up from a long sleep. I was able to feel content without anything good happening, I was just happy to "be" again.
If you usually feel like this at this time of year, it could be seasonal affective disorder. Getting less sunlight can mess you up sometimes.