Propranolol. I had a generalised panic disorder which made me virtually housebound for a good few years in my early twenties.
Propranolol got me out of the house initially, but the one thing that helped me on the road to recovery was accepting that panic attacks were a part of who I was, and not something to fight against or run away from.
I haven't had a full blown attack in about a decade now (wahayyy!), but I have had some very stressful times in my life (death of both parents, redundancy, new jobs etc) and during those times I've felt the old feelings coming back, but for some reason they only get to a certain level now before melting away.
I think that you have to find your trigger points and approach them gently, one by one.
You need to recognise what makes it worse for you -mine are not getting enough sleep, hangovers and pmt. Understanding this gives you an understanding that it's not the situation that's making you panic, but your underlying mental state, which in turn makes it easier to to confront the things that you avoid in case they trigger an attack.
Once you've recognised your triggers, you can eliminate them before you plan to do something that you worry will trigger an attack.
Restaurants was a biggie with me. I started by going alone to a cafe for a cuppa on a day when I was feeling good, having had plenty of sleep, no pmt, no hangover etc. I then notched it up over time (lunch somewhere quiet, pizza in the early evening) until I could go for dinner with a friend without thinking to much about it. Don't get me wrong, if I have a plan to eat out with a friend, I won't throw caution to the wind and will always make sure that I get a good night's sleep and not drink anything the night before, and that's part of having accepted it as part of me.
I'm not a doc, or a psychologist, just someone who has been right down there with constant anxiety so understands how debilitating it is, but also knows that there is light at the end of the tunnel, and it isn't necessarily a train coming in the opposite direction
Good luck!