Really awesome to see this.
I've been (wether I knew it or not) battling a healthy mix of depression and anxiety pretty much my whole life. On top of that, I was also fairly recently diagnosed with pretty severe ADD; The doctor who I worked with for that literally said he was amazed I finished high school with my results. All of that together is a really volatile mix. There have been moments of crippling depression, anxiety attacks, massive internal guilt trips, all-consuming rage, and lack of any feeling at all.
I didn't seek any professional help until college, and it was an awful experience. The people I worked with didn't listen very well, which led to me being on medications that did not work at all, or worse even amplified my already massive mood swings. After a few months of this I just stopped going, feeling like I'd rather deal with what I had before than what I was getting.
For my last two years of college I was struggling to get through. My grades declined and I lost interest an anything I was doing. I also essentially became a functioning alcoholic for a time, bringing bottles of "tea" to class, and drinking myself stupid at home when alone. I finally managed to get through it, didn't go to my own graduation, and attempted to get life going.
During all of this, I had a girlfriend who became my fiancé and then my wife. After a bit of financial struggle I finally got myself a full-time job as a graphic designer, and for the most part everything was good. Even with everything going well, I still had a kind of "hollow" feeling.
During a really low internal point, my wife finally got me to go back to seeing a professional. This time, it worked out. I've changed who I've worked with since then, but I am still going and the improvements have been vast (although I still have a long way to go). I currently have a therapist and psych who not only listen well, they also help me through things and keep in contact with each other. Right now I'm seeing my therapist about once a month and I'm on a bit of a cocktail of medications that, for the moment, are working.
There are still bad days/weeks/months, but they are a lot easier to deal with than they were before.
Now for my preachy advice column;
The first step is the hardest - Try not to beat yourself up if you haven't scheduled an appointment or even found someone yet.
Shop around - Only you know what works for you and what doesn't, and there are plenty of professionals around.
Be honest - I've had friends who were improperly treated because they weren't honest and open with their therapists/psychs.
Well that's about all I've got, thanks for letting me rant.