I think I just reached Nirvana...?

I used to meditate with binaural beats and it made me feel good. I just tried some guided meditation on YouTube for the first time. But this time it hit differently.

The person said "I will count down from 5 and each time the number changes you will feel more and more relaxed" When he reached zero I felt my eyes starting to move like I was in trans. It felt like the time I was in hypnotheraphy. But way more intense.

After my eyes just started to move, I felt like the whole world was moving and it was as if I was watching it happen. Then it got more intense and I was beyond the existing universe and the whole universe was spinning in nothingness. At that point I just kind of panicked and that made me lose that concentration. (And no, I didn't use any substances or anything like that)

Wow... What an experience right? So, a few questions:

1- What in the ... was that? Lol. What is that called, did I reach Nirvana or open a chakra or something?

2- I don't want to panic during that experience. Altough my whole body was calm my mind just said "Nope! Something's wrong, snap out of it!" and that experience just ended. How do I stop myself from panicking?

3- I asked ChatGPT and it said "you could have opened your crown chakra". What do you think?