Sorry you went through the intense panic.
The mind can do amazing things. As quickly as you go into deep panic, it can also realize that there is nothing to panic about. This sometimes can happen in an instant.
We build these mental models about what is happening. They are all wrong to some degree, yet we want to cling to them and truly believe them. Humans are like that.
Try not to feel too bad about what happened. You were trying to explore in a safe manner. Yes, you may have made a couple small mistakes, but we all do. At the end of the day, you were always safe with strong vitals (while giving a boost to healthy neuroplasticity), which is not allways the case with dangerous drugs such as alcohol or opiates.
What you went through while actually being safe is a good example of how powerful our minds can be at creating something that we feel is deeply real. If the memory of the experience fills you with panic again from time to time, I would try not to fight it. Allow yourself to go through it again and observe your panic. Let your mind finish going through the memory. Have you ever had a song stuck in your head? The best way for the song to stop bugging you is to finish it. If you keep on interrupting the song and pushing it away, it will take longer to move on.
That's the mind's job, to create a sense of reality out of a partial understanding. Allways extrapolating and filling in the gaps with a sort of continous hallucination, even when sober (there is a reason serotonin and dopamine look just like our favorite molecules).
I try to take what I perceive as reality with a grain of salt. It's just an approximation. I used to have strong convictions and pass judgement, but now I see that one can trap themselves in a mental cage with such ideas, just how we can all get trapped in a bad trip. Even though I say this, I still catch myself passing judgement and having bad trips, so this open-minded observer state that contemplates beauty and mistery is a work in progress.
I commend you for being an explorer of conciousness. I wish you best of luck if/when you decide to try to explore again. At the end of the day all we can do is try our best, and forget the rest (easier said than done though).
Cheers and love to you.