I believe you should start in small ways. Take a very big leap of faith in yourself, take a deep breath, as though you were going to jump in at the deep end of a swimming pool, and volunteer - yes just that - volunteer. Volunteer to make some cakes for the local church coffee morning. You don't even have to go to said coffee morning - ask someone to pick them up from you - and then wait for the feedback, which will be very positive. This in turn will give a boost to your courage in order to take the next step. This may be actually going to help - you know - waiting on, washing up- that sort of thing. It all sounds very mundane, but who cares about that? it can be a lot of fun washing up for a lot of people when you're doing it in good company, and after the first time, you'll certainly be asked back!! You'll be starting to make friends in a gentle un-threatening way. You'll be in control, and you can take or leave as you please
After this, you could maybe volunteer to take part in a course aimed at helping others, and you own experience of depressive illness will help you empathise , thus causing more positive feedback for you, leading to another little boost in your confidence around people.Take your courage - and you do have courage - into your hands and take that first jump into the pool and see what happens.
It all starts with that deep breath before the plunge - remember, deep breaths leave no room for butterflies.