So you have an anxiety disorder, as well as depression. I really think those are two distinct problems. It is common for depressed people to also suffer from anxiety. (That's true of me as well.)

In your case, your anxiety disorder may even be a bigger problem than your depression. Most people with depression are not as severely anxious as you are. So it might help to thing of them as two separate illnesses. Of course, one illness can aggravate another. That's true with both physical illnesses and psychiatric illnesses.

Having a therapist who helps you plan a daily routine is an excellent approach. The benzo may help reduce the anxiety. An antipsychotic might also be worth trying, since your anxiety is so severe. They can be calming.

There certainly is a physiological dimension to anxiety and depression. You can be born with biological vulnerabilities. I, myself, believe that most people with depression also have other factors that contribute to the problem. I think of depression as similar to cancer. Usually, there are multiple factors - including behavioral ones - that contribute to developing this disorder. (Like - smoking can cause lung cancer. But some people smoke a lot and never get cancer. And some people who never, ever smoked get lung cancer. No way to know for sure exactly why a particular individual gets lung cancer.)

Once you get depression, it changes your behavior in ways that make the depression worse. Consider emphyzema. Once you get it, you find it very hard to move around because it makes you so tired. So people with emphyzema will sometimes avoid doing anything at all. That leads to further weakness and it gets even harder to do anything because the person loses muscle strength and the lungs get further impaired in their oxygen carrying capacity. Depression works the same way.

Recovery for you will take a long period of reconditioning yourself, which takes a major commitment on your part to do things that are very hard to do right now. But, if you force yourself to do them, it will gradually get easier. But improvement can be so slow and gradual that you think it isn't even happening, and that can make you so discouraged you give up.

Start by trying to get just a little more active, and stick with that for a while before you push yourself a little harder. Even if you accomplish just one goal a day, give yourself a pat on the back. The smallest thing you accomplish can be a big victory in beating back the disease of depression.

Meds may help, but a lot of the recovery depends on you changing how you spend your time. We have a thread where we give ourselves a pat on the back for taking a shower. I think it helps to celebrate the small successes. For a depressed person they're not small.