Used - to - be

I used to be a happy girl. I use the phrase "used to" doesn't mean that I am not happy with my life now, just have a feeling that I am not like how I was before. Sleep less, talk less, even smile less.
When the assignments, tests come, everyone just scratching their head, hoping to have some ideas in solving those problems. Yet, what's usually happen is, I look at you, you look at me and there's no conclusion come out after a long discussion.
My friend told me not to complain too much, as it's what we called "life" is.
Yea, perhaps it's true. We should see everything at the positive side, instead of blaming, blaming and still blaming :P
And now, I am learning. =)