Processing is more about finding out why you're doing what you're doing. Why are you isolating? And it's not because of depression (unless you believe it to be chemical imbalance then you'd need medication). Does that make sense? That it's the isolation causing the depression. I'm assuming this because you say you think the depression will get better if you socialized more. So processing why you're isolating would be the key to therapy. Sure it's nice to have support from someone like a therapist, but that's not the point of therapy. You can socialize (paid or free) with many other people in life (cashiers, hairdressers, masseuses, etc.) without much effort.