Panic Attacks

So here's a little back story:

When I was thirteen I was diagnosed with generalized anxiety disorder. A few weeks shy of my fifteenth birthday, it had transformed into full-blown panic disorder mixed with agoraphobia. I couldn't even think about going outside to get the mail 20 feet from my house without hyper-ventallatiing and thinking that if I did panic (which happened 8/10 times when I stepped outside) that it would be the panic attack that made me have a fatal heart attack.

When I was seventeen we moved an hour away from my childhood home to where my parents grew up. We were seven miles away from the main road, then it was another seven miles into town, which made a grand total of fourteen miles just to get to the closest store. My parents thought the peace and quiet would help me calm down... but it didn't help my anxiety any.

Finally, when I was eighteen I decided I had enough. I started seeing a counselor, went back on my medication on an as needed basis, and just had hope that this would fix me.

At first, my panic attacks shortened. They would be just as intense but they wouldn't last nearly as long as they had prior to counseling. Then they slowly became less intense.

In July of 2016, my sister, who lives three hours away, asked me to move in from August 2016 to March 2017 to become a full-time babysitter so she could go back to school and work. I seriously thought it out, weighing all my options and thinking of a million and one different excuses to deny the request. But no matter how much I told myself I just couldn't do it, I wanted to. I wanted to see if I could actually handle technically being on my own.

So on August 20, 2016 (my eldest niece's 8th birthday), I packed up after the party and left. That was also the very last day I touched my anxiety medication.

Now, its November 17, 2016 and I still haven't touched my anxiety medication.

But, a couple of days ago, I was in Wal-Mart with my brother-in-law just walking around and shopping. It was a little bit busier than usual but it was nothing that phased me the other day when we were there buying hair dye. As I was walking with my brother-in-law I noticed my legs felt like they weighed a ton. I know I was still walking but I just couldn't move my legs. My chest burned so bad. Then, all the sudden my vision went black for about 10 seconds and I felt myself fall back. I caught myself, blinked about 900 times and told my brother-in-law that I needed to get out.

Once we were out of the store I was on edge all day. Even when we got home. I felt like everything was out to get me. That night I had trouble sleeping, even had an anxiety attack bad enough to wake my sister up at 1am to help me come out of it. She asked me if I wanted to take my medicine and I just cried even harder because I didn't want my brain to win. I needed to fight in by myself.

So, my question to you, lovely readers, is has anyone ever had that experience? I, personally, have never had my entire vision go black before. It was an immensely scary experience and I just want to know if it's... well... "normal"?

Thanks for reading (even though this is like 10 miles long), and I'm looking forward to your responses.