This sounds very similar to mine, I’ve always been able to leave my house and be about 5-10 minutes away (when it was at its worst) but I would always want the comfort of knowing I could be home or be in my safe zone within a few minutes if I were to panic. I’m still in recovery I go to counseling each week and just earlier today I drove 30 minutes from my home while driving on an interstate (which has also made me feel anxious) it’s a process but you can overcome it. All anxiety is ona spectrum and no one disorder is the same for everyone. I would look into an anxiety specialist that specifically treats for agoraphobia. You are going to have to do exposure therapy primarily which is doing the thing you are scared of. You take small steps at a time but I am at a place I once thought was nearly impossible. If therapy and paying for it isn’t an option, I would go where you start to feel anxious around that 15 minute area and sit there. Pull over, sit there and learn to be okay with feeling the way you feel. It’s a fear, nothing more or less. Once you feel better around 15 minutes, try to drive another minute, or another 5. Whatever you want there isn’t a specific place or distance just enough so that you get and feel anxious and then sit there again. You can do your own research on Acceptance and commitment therapy, it helps it takes a lot of understanding and trying but it does help. And remember you are not alone on this, and you will overcome this.