How can I become more optimistic?

It seems like me and several friends have been going through a bit of disappointment/boredom with life after graduation. I work long hours and am too tired to socialize like I did when I was in school. I was just wondering if there's such a phenomenon of post-college depression?

Are there any techniques for controlling crying? I doubt that my problem requires clinical attention; however, it frequently manifests itself as a serious handicap. During conflicts (particularly with professional superiors or with significant others), I find myself unable to defend my position, which only makes the problem worse. Sympathy only tends to aggravate the crying and it is impossible to stop once it starts. I am a twenty-four-year-old graduate student, and I don't seem to be growing out of it. Any suggestions would be greatly appreciated.

I'm desperate (a permanent state, I suppose, not only for me, but also for most of my fellow human beings). I've forgotten the reason why I'm on this Planet. My life seems so senseless, eating, sleeping, going to work, hobbies, of course, while all around me, the world is tumbling down. How do I put some meaning in my life?

I am a 22-year-old male grad student, now starting my second semester at in graduate school. I have been doing very well academically, but my studies and my work-study job leave me absolutely no time for a social life! I have not been on a date since I got here; though I meet a lot of interesting people, and am in the habit of collecting their phone numbers. However, I can never seem to find any time to spend with them. Sometimes this really depresses me. I have noticed that I have lately been smoking much more heavily than I used to.

I was adopted when I was two and a half years old, and I still have a lot of issues from it. I don't really like myself and at times; I feel like I don't know who I am. I never let myself become close to my adoptive family, and still feel uncomfortable and out of place around them. I don't have many friends. I isolate a lot and don't really trust people. I am always scared to make friends for fear that I won’t be accepted or liked. Growing up I often turned to drugs and alcohol to escape these feelings and to feel comfortable with myself. The problem now is that I am 22 and I have a two year old daughter. I feel like I need to get over this so I can be a good mother to her, and raise her to know and love herself. I feel lost, what can I do?