I am so, so sorry that you're experiencing this and I completely understand and identify with the desire to "Do Something," regardless of what that "something" might be.

First, please be patient.  I know that you're in misery, but mental health issues aren't like a gaping wound - symptoms are not always obvious, and there are many clients that are not 100% truthful or honest about what's going on.  For instance, certain personal information about childhood experiences and personal choices are excluded because the client is ashamed or afraid.  So..........be patient.

Next, be honest and truthful.  Tell the mental health people everything, even if it makes you appear less than perfect.  Unless you tell them that you are planning to cause harm to someone else, anything that you tell them (and, I mean anything) is kept in the strictest confidence - they are not allowed to discuss you, your issues, your treatment, or your progress with anyone, by law.

Next, have more patience.  Emotional recovery, mental health progress, and treatments require time.  There is no magic wand, no magic pill, no magic technique, no hypnosis, not one single thing that will solve all of the issues - there isn't.  Come to accept that fact, even if you don't *Like* it, and be patient. 

You will likely be given a number of tests and a mood journal - be diligent in recording in your mood journal.  Dates, times, feelings, impulses, actions, etc..........get it all down. 

It just takes time to sort things out.  And, you may not *need* antidepressants - these medications are being prescribed at an obscene level because the medical experts that prescribe them simply don't have the knowledge or skills to address EMOTIONAL health.  They just don't.  It's a whole different discipline that requires greater finesse and knowledge base than other disciplines do.  Sure, a doctor has a great deal of knowledge and training, but it's pretty rote - meaning that stitching up one laceration is going to be much the same as the next.  With emotional health, each individual is different with different histories and behaviors, etc.  Having typed that, there are a host of patterns that can point to specific disorders and issues, but it takes a lot of time, patience, and skill to address them.

When you feel the fear becoming overwhelming, practice the technique of "Getting Into The Now" which is to literally tell yourself where your left hand is resting, then the right hand, then recognizing the air current, the temperature, and everything that you see, physically feel, smell, taste, and hear until you begin to feel more calm. 

Brightest blessings to you.