Do we have to assume you're from the USA?
Cause it is going to differ per country.
In The Netherlands it goes like this.
1) You look up your health insurance to check how you're insured. (Ideally, you try to extra insure at end of year for whatever you think is necessary but it is almost always never a net profit, or extremely small.)
2) Then you call up your doctor for an appointment. If you think your discussion with your doctor requires extra time, tell that to the assistant.
3) You go visit your doctor and explain the problem(s) you have. He/she'll likely give you a reference for a psychologist/psychiatrist (latter if you are interested in using drugs such as anti depressants). This reference is important for insurance reasons.
This is where the advice from me actually ends since I'm not your doctor! You have found a mental health professional. From there, you can work out which treatment you want, or get directed towards more/other professionals (I gave some examples). One last piece of advice. Avoid all the paranormal BS. Stick with conventional science (mindfulness is conventional science, btw).