Struggling with Agoraphobia: How to Manage Anxiety When Reality Confirms Your Fears

I haven't left the house on my own in months. It seems like every time I do, something awful happens, and it just confirms to my agoraphobia that I shouldn't have gone in the first place. Even when I manage to psych myself up and get ready to go, in the rare case that all of that doesn't make me too tired/put me in too much pain to go, I start to worry that I will be in too much pain once I get where I'm going. Often, even when I go places with someone else, I have to go sit in the car before we are done because I'm in so much pain. Does anyone have any tips for managing this kind of anxiety when reality seems to be saying that you're correct to be anxious?