Every minute of every day was a battle when my anxiety and depression were at their worst. I feel your pain. For me, my anxiety was not behavioral or environmental. Sure, certain things triggered it, like seeing anyone or talking on the phone, but it was not brought on by my thoughts and it was not something I could control.

Try to keep stress out of your life as much as possible. One of my problems was I became completely withdrawn and stopped communicating with friends completely. Like you said, sitting in a room by yourself is often the worst thing for the depression/anxiety. Once I accepted the anxiety in a way, I started reaching out to others.

Let people be there for you. I've learned how to effectively communicate with others and let them know exactly what's going on, which has helped. For example, if I'm getting lunch with a friend and have horrible anxiety, they might not be able to tell I am shaking and sweating and my heart is beating out of my chest. Letting them know exactly what is going on has helped, instead of trying to hide the anxiety. I simply acknowledge the anxiety then let it pass, instead of trying to avoid it.

Hope things get better for you, I know it's tough. Try to remind yourself that it will all pass eventually!