Also exposure therapy might help.
Welcome.
What you describe is classic panic disorder with agoraphobia and derealization. If I'm saying things that don't make sense, do a little research on those terms, you'll see what I'm talking about.
The agoraphobia, or avoidance (being housebound most times) is a result of reinforcing the panic by fleeing a place or situation when panic strikes. You start avoiding those places, then more and more places, until leaving home becomes difficult, which is where you're at. ANY situation that you perceive to be one where you could become "trapped" with no easy escape (traffic jam, amusement park, concert, bridges, tunnels, CT scanner) probably causes you great anxiety, if not panic.
You probably also have a good bit of "anticipatory anxiety" going on too. That's when from the MOMENT you find out you have to go somewhere (family obligation, doctor's appt)...you worry non stop, and "what if" yourself silly. "What if I get stuck in traffic on the way and have a panic attack?" "What if my car breaks down and I lose control and end up in a psych ward?" Sound familiar? I bet it does. That "what iffing" and imagining the worst case scenario is also part of this anxiety disorder. It's called "catastrophizing".
Derealization is a symptom of chronic or severe anxiety.panic. Its a change in the perception of your environment. Everything looks "unreal", "dreamlike", or like you are looking at the world through someone else's eyes...or like you are watching a movie. Everything just looks "weird" or "off".
All of this ringing a big bell? If so...then what do you do about it? You seek professional help. Have you ever sought out treatment for anxiety/panjic...and if so, what? Did it work?
The most common approach to treating the condition I UNOFFICIALLY diagnosed you with (as I'm no doctor...that was just my take) is with meds and therapy, specifically, CBT or cognitive behavioral therapy, which is where you will learn how to break that cycle of anxious "what if" thinking. You will learn how to endure panic attacks and take the power away from them. The meds help to control the symptoms and decrease your overall anxiety level, but the therapy is where you really work to change your thought processes. It helps you send the message to your brain that there is NO need to panic..there is no danger...only what is perceived in your mind.
I can reassure you of a few things (having lived through it myself...exactly everything you wrote I could have written, down to the traffic jams), while panic is terrifying, what you're feeling is ONLY sensations and emotions that can NOT harm you in any way. Nor will you "go crazy" PLENTY of people suffer from panic attacks and the resulting problems (avoidance, agoraphobia, derealization, etc)
Take that first step, and get yourself an appt with a psychiatrist who can assess you, properly diagnose you, and start giving you treatment options and hook you up with a therapist. You are going to have some trouble at first, just GETTING to your appts (due to the agoraphobia), but it is crucial you find a way. Have someone drive you, try to choose a doc closer to home...whatever you need to do, but you need to make it happen if you want to overcome this.
Also, getting better is a process, and it takes time. Don't expect miracles or overnight fixes. While the doc may give you medicine to help ease the anxiety...it not going to just go away. You're going to have uncomfortable moments, but that's all part of the treatment.
Let us know how you're doing. There's a wealth of info here...stick around!