So, last year, I went through divorce, started transition, did work and school full-time, had a bunch of shit go wrong, had to make all new friends (because I had none when I separated from my wife), found out my mom doesn't love my dad and that she was suicidal, and god knows what else. It was a rough year that has definitely extended into 2012. I had several periods of severe depression where suicide seemed like a really smart, viable option. The first major bout resulted in me seeking therapy. The second major bout resulted in me eventually taking Zoloft. Both of these things together helped immensely. Therapy alone, I learned, wasn't enough.
Now, with being in the medical field, I understand. My ex worked at a major hospital and she was always really embarrassed for them to know anything personal and private about her. She never got help while the two of us were together, but I hear she's doing a lot better now after getting on some meds. Likewise, my bestie works for that same major hospital and it took me months to convince her to try to see someone. All I can say to that effect is that everyone has problems. Getting over your embarrassment and admitting that you need help doesn't make you a weak person. If you get therapy or start taking meds, nobody will care.
Sans those things above, there is one other thing I did that I think made a huge difference. I took the word "no" out of my vocabulary when people asked me to do things. It resulted in me having such a busy social calendar that I didn't have time to think about depression. That whole "fake it until you make it" demeanor where you have to put on a happy, smiling face can mitigate some of the effects of depression. Yes, 90% of the time, it was really hard to find the motivation to get dressed and get out the door, but putting one foot in front of the other and not being a flake forced me to be around people who genuinely liked me. Its definitely not a cure-all, but it helps.
Hope you get better, hon. :-)