It's hard to say. When I was at my worst in the dot.com bust, I wondered if I was clinically depressed, or bipolar. The wonderments were certainly self-diagnosis. But then I approached it rationally: do professionals think I actually have a problem? I went to a free bipolar screening clinic at a local hospital. It took a little research to find out that such a thing exists, as I didn't have a doctor or health care, but the info was discoverable on the internet. I talked to the screener for maybe 20 minutes, about what things were like. Became pretty convinced by her, that I didn't have a medical malady. I had very predictable life stress from my circumstances, and what I really needed was job counseling, not medical interventions or pills.
I did reorient my problem towards "what is my !#$## career now, what is it going to be, how shall I pay the bills?" I got through it, mostly taking pragmatic survivalist courses of action. Didn't solve anything long term, I'm living out of my car with my dog. But I think I'll get the great computer game done someday and it'll all be better. Anyways I avoided going down a wrong path of doctors and pills. It wasn't my problem.
Sometimes people will try to tell you "mental stuff" is your problem, and that you should be seeing professionals and taking psychoactive medications blah blah blah. Family members who are worried about your behavior may push this kind of stuff at you. Well, frankly, quite often in life you don't need a shrink or a pill, you need to take action on something. That's not true in every case, but I bet it's more true in a lot of cases than not.
Another thing I did back then, was attend 1 session of a depression / bipolar support group. I got to see what I'm like by comparison with people sharing their actual depression / bipolar stories. I didn't exactly fit. But watch out, some people in such a group will inevitably project their impulses on to you, and tell you you're undiagnosed OCD or something like that. Don't fall for it. It's ok to have doubts about yourself, but someone who's actually bipolar or OCD isn't the person who should be prognosticating your actual condition.
Like I said, the screener at the clinic helped me figure out that what I really needed was job counseling and not pills.