I have had the same problem for 40 years! No, we don't all feel confined to the house, as you do, although I can quite understand how you feel. I was concerned when I read that you, "managed to find a girlfriend". You have a problem, yes, but so do others - hence this site! Please don't think of yourself as someone who 'managed' to find a girlfriend but as someone who 'had' a girlfriend. I'm not too sure about the agarophobia thing - it will only perpetuate a lie and that can get you into all sorts of trouble and give you problems. Please remember that people don't actually see you as a 'person with a problem' but, as a person. It's very, very hard to tell people about this thing that troubles us - embarrassing, to say the least of it - but it could maybe help. I told my second husband and found that he had a problem urinating in public toilets. I expect that I am much older that you and I have found people with problems, different from mine, but very real and painful to them.
You seem to feel that you are worthless, well, you aren't! I still suffer agonies, when I stay in other people's houses, am at an airport, oh hundreds of places, but that's us. We have this problem but I don't think that it makes us freaks, just different.
I wish that I could solve your problem but I can't. If I could, I'd have solved my own! The only thing to to, I feel, is to try - and it isn't easy, I know - to live with it.
I realise that I haven't really helped. I just wanted to let you know that you aren't alone and that you can 'rise above it'. It's how you are and you are none the worse for it.
Take great care.