I'd have to agree with it being a panic attack - albeit a severe one with added complication of being extremely stoned too. I can see what you mean about there being some similarities to the symptoms of SS on paper but I think that is all it is - on paper the symptoms of SS can look remarkably similar to a whole range of states and conditions but in actuality they are so much more intense and beyond imagining that it's really unmistakable as being the real deal. I would also question how and why cannabis would or could trigger an intense overload of serotonin to the extent of causing SS - cannabis doesn't release serotonin afaik, no specifically anyway. It sounds to me like you took a shitload of MDMA (or possibly MDA or a combination as Mitsubishis did come in various combinations as I recall) and eating cannabis afterwards whilst your brain was still somewhat depleted and recovering triggered an unusually intense panic attack which was intensified and exacerbated by the fact you were also stoned - a bit of a spiral effect with the two feeding off each other and causing the symptoms to become far more pronounced than would perhaps be the case if your brain was fully stocked on brainchems and you were generally fit and well as opposed to recovering from a night of pretty heavy drug use.
To be fair, I only really have my own experience of SS to be going on and what I have read on the subject in general and if I were to write out what happened to me there would be points of similarity - the raised heartrate, the rolling eyes, the distorted perceptions - but I would strongly suspect the degree of symptom would be in a whole other realm to what you describe. For example, one of the most noticeable symptoms is fitting and convulsions (caused by the massively raised body temperature - I do believe what kills you with SS is basically boiling your internal organs to mush... well... along those lines, mush may be a slight exaggeration for effect). I don't think a person would likely be diagnosed with SS without the convulsions as it's a pretty intrinsic cause and effect thing.
Another example where it would be maybe more a matter of degree than complete difference would be the delusional aspects. You describe hearing voices and interacting with a television not realising it was a television - which is pretty delusional behaviour - but it's also not entirely uncommon for somebody who is incredibly stoned (particularly when they're using it orally which is waaaaaaaaaay more psychedelic and intense than smoking ever gets). The delusions I had were completely immersive - there was no sense of confusion or of acting strangely because I had no sense of self or of any other reality to compare my current state to. There was no internal monologue or feelings of panic or confusion or fear or anything - I simply reacted to compulsions, perceptions (however drastically altered they happened to be) and as such spent several hours marching about pissing on stuff (with me being a Storm God and that (at the time) - it's what we do, dontcha know) in between being collapsed on the mattress bent double (backwards) convulsing. Written down our two experiences would perhaps not seem so very different (aside from the more physical aspects perhaps) but I'm fairly sure that would be due to an inability to put into words or truly convey quite how it was in reality because there really are no words that can express the sheer ferocity and overwhelming, all-encompassing nature of symptoms that on paper seem fairly common and generic.
Obviously I'm not a doctor nor an expert on SS so I could never tell you for an absolute fact one way or the other but it really does read to me like a severe panic attack combined with the expected effects of eating cannabis - first time I ate cannabis I was borderline delirious for the best part of three days as I recall... or don't recall much of at all actually. I think people greatly underestimate how much stronger cannabis becomes when taken orally and everything you describe fits perfectly with a person eating cannabis whilst perhaps not at their best physically and mentally. Or just from eating cannabis at any time for that matter.
I'd say as a broad and general rule that if a person asks whether they had SS they didn't almost by definition - it's just not a thing there is ever any doubt over. It's also worth thinking about what it was that could possibly have caused SS in your situation as there was nothing that could conceivably have caused SS involved that I can see. Ecstasy alone doesn't tend to cause SS - in conjunction with certain other drugs, yes, but alone, no - and even if it did it was days later when serotonin levels would likely still be lower than normal rather than raised to life-threatening levels. There is no reason for SS to even be an option that I can see really. It has often been pointed out that the symptoms of SS fit with the symptoms of being intoxicated on just about anything if you just see them listed without the added context of severity - it's not uncommon for people to be convinced they must have had SS (was one fella in ED who was convinced he'd had it "dozens of times") but I really do think that if those people were to witness a case of SS actually happening they'd spot the difference rather easily.