Personally I finally decided to go in and talk to my GP, or regular doctor, at the end of 2013. He was really nice and understanding. He referred me to a psychiatrist -- they specialize in mental illness so they're really the ones to make the "official" diagnosis. Just tell them each about all the symptoms you've been experiencing. Then you can discuss with the psychiatrist how to proceed with your treatment, including seeing a psychologist for therapy or starting medication. In my case, my GP started me on generic Prozac, though I continued seeing the psychiatrist and changed to different medications.

When I decided to get help I knew I had major depressive disorder and social anxiety disorder, but was additionally diagnosed with generalized anxiety disorder and a possible autism spectrum disorder. More might be going on than you know, or perhaps less. It felt good to finally get a proper diagnosis, though, instead of guessing myself for so many years.

I wish you well.