Ah, I see. Well, I'm glad that you're okay, and I'm certainly no medical professional, but I have to say, I don't think you were actually in any real danger.
The paleness and high blood pressure you describe are actually just normal side effects of DXM. I'm not sure what causes the paleness, but it's not dangerous. As for the high blood pressure, that obviously would be bad if you had it all the time, but for the duration of one DXM trip it's not really damaging; many common recreational drugs, including the classic psychedelics, cause a rise in blood pressure, but it's not considered a significant risk factor except with heavy abuse or in people who already have cardiovascular issues.
As for the numbness and the blackouts, those are actually just a part of the intended recreational effects of DXM. They would be better described as dissociation, the numbness being a partial disconnect from your bodily senses, and the blackouts being a total disconnect so that you don't even realize you're still moving around while you're lost in thought, causing the sensation of just spontaneously appearing at different places around the house. These effects can be quite intense especially for someone not used to or expecting them, but again, they're not dangerous, at least not beyond the risk of injuring yourself somehow and not noticing because you're too out of it to feel anything.
With regards to the freaking out and thinking you're going to die, that's a pretty common reaction to almost any strong mind-altering experience that either wasn't expected or just isn't being handled well psychologically. In addition, DXM has a stimulating effect for many, and that can really make a panicked mindset even worse. I won't tell you that if you try it again you'll enjoy it, because it's honestly heavy enough that a lot of people don't even when they feel safe on it, but you should know at least that DXM on its own and when not abused has very little risk. It can be uncomfortable, yes, but not usually dangerous.
Finally, about the doctor, again I not a medical expert, and in almost any other situation I should say absolutely you should listen to your doctor, but when it comes to coming in on drugs afraid that you're dying, I would caution to take everything they say with a grain of salt. Even doctors spout a lot of completely false information about recreational drugs based either on ignorance or trying to convince you that drugs are bad for you. In this case, especially considering what substance it is, I could definitely see them trying to scare you off of it by telling you were "close to" a seizure, even if there was still no risk of you actually completely having one.
Anyway, just my thoughts on the matter. Not that under-researched chemicals are necessarily better, but if you are interested in finding some more worthwhile dissociatives I would recommend doing some more research on the current analogue scene, like the arylcyclohexylamines. Since those started coming around I've barely even heard anyone mention DXM compared to before.
