Re: exposure
It's the way forward.
Set targets and take small steps. You don't need to attempt what seems massive to you straight away.
The exposure allows you to build confidence through experience. As you get comfortable with each step you slowly push back the boundary. Confidence is key to facing our fears.
For example, you may want to spend a week just opening the door to the outside.
Once you are relatively comfortable with this you can try to step outside.
As you become ok with this you can then look at going to the end of the road.
You get the idea.
As you gain experience from doing these things they will come to mean less and the anticipatory anxiety (which causes half the problem!!) will lessen and fade away.
Good luck with it.
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Life is what happens while you are busy making plans.