Before i describe what happens to me, ill explain my condition.

Im 26 years old, Male, overweight. 0 conditions other than Anxiety.

I used to smoke weed (4 years dry now). Had a panic attack and quit
.
For the anxiety, I've been on Propranolol 40mg, 3 times a day since, important: The "depersonalization" started before the medication.

It was at its worst 4 years ago, went away and started up again recently.

When i was a teen:
I remember it happening when i was urinating, standing up after a long time sitting, id feel my mind just check out out for half a second and think "where was i just then?", it didnt feel like a second, felt almost like id lost the concept of time. it felt like my brain checked out for a short second and came back, but id manage to stay standing up, in control and aware of what happened.

What happens now:
This started 4 years ago, went away after weeks and weeks of torture. Came back recently.
I could be doing anything (standing, sitting, walking). Majority of it happens when im not doing anything or using all my concentration. Ok so, Visually, im seeing what im seeing, like the computer screen, or whatever, but my mind just fogs out, i forget where i am (not forget, i know my name, where i am, what i was doing but its like my consciousness just flips for a second) and then remember a second later, and this happens continously repeating itself, unable to process my visuals as they are happening, its very frightening.
To an outsider i seem fine, i recall everytime its happened. Its like a huge scary mind fog or lapse where my mind checks out and feel disorientated (Mentally). Like a Jamais Vu, but rather than everything seeming unfamiliar, i actually cant process what im seeing, 15 seconds ago, for you might seem incredibly short. But for me, when this happens, 15 seconds could seem like ages. The more i let it happen, the more worse it gets. one time, it started out as "Oh it just happened", i forgot where i was, mentally came back in a second and was unfamiliar with my surroundings, or felt like my mind just went somewhere. Then it happened more intensely because i was thinking about it. It got more and more intense to the point where id lost the concept of time, like id been zapped out for years and shot back, but it was all just a couple of seconds. I then felt a panic attack coming on and had to walk about to calm myself down. Deep down i knew most things about where i was, my name, but its just like the part of my brain that receives what im seeing, turns off for a second, comes back and then turns of again.
Even when i try to ignore it, its still there but not as bad. But it definitely helps when im not thinking about it.
Its been happening for 2 hours now, it was very intense before, its still happening now as im typing this but minimally, i dont feel it much when im focused on something.
The main concern for me is that it happened when i was a kid, before the panic attacks even started. It only lasted for a second back then, and now it seems like its extended to however long i can think about it.
Im scared that i can die from this and it might be something wrong with my brain or some sort of tumour