Me too. Diagnosed at 16 and I'm 24 now, but it really started when I was about 12/13. Its definitely something you need to at least have evaluated. Some people suffer depressive symptoms only occasionally, some more consistantly, some more or less severe than others. Some people can deal with just counseling, others need medication along with it. Some people will start hurting themselves, some won't. It could also be like that old commercial they had saying that some doctors would diagnose depression not knowing that the patient was also having manic episodes.
Honestly..don't put the doctor off, thinking "I'm just in a funk, it'll go away". At least go and see what they have to say. The PPs are right, if you end up going to a counselor, keep in mind that you may not click with them. You need to feel comfortable with whomever you're speaking to. I went twice to a counselor when I was 13, but my parents were in the room during the sessions, I wasn't going to say anything in front of them so I just told the doctor I was fine. I was even too embarrassed when I was 16 to tell my mom that I needed help. I had a checkup appointment with my normal doctor, and told her how I was feeling and actually asked her to tell my mom she thought I should go in because I just couldn't say the words.
So all these years later, I'm out of counseling, but still on meds. It took a lot of work to get to the point I'm at, different counselors, different medications, and different people being in and out of my life. I think (and I'm not trying to say this is you or anyone else that replied) that depression as an emotion and depression as a "disease" are often confused,and some people will go and think they can just get a pill and things will get better. That's really not how it works, my point being is there can be a lot of work to do, but it's worth it.
Feel free to PM me if you have any questions, or even if you just want to talk.