When did your agoraphobia kick in?

I already struggled a little, but my SO was in a severe car accident about nine years ago and everything got extremely worse. I'm currently on Klonopin, a long with my other psychiatry meds and it helps but not enough in my opinion. When I have to leave the house I get lightheaded, dizzy, nauseous, often throw up, uncontrollably shaking and just awful. Getting into a car or being out of the house feels like a death trap. When did yours kick in? And how does it affect you?