Does this sound like serotonin syndrome?

Late at night when my mom goes to bed, she gets nauseous, has diarrhea (sometimes vomiting), she feels like blacking out, feels like she can’t breathe, etc. I finally witnessed it myself and she felt clammy, kind of like a cold sweat but felt warm at the same time. She was shivering. Also she has muscle rigidity, and almost like her reflexes are hyperactive for no reason. For example her hands will curl up in a claw like position and it either hurts her or she can’t feel them at all. She has general muscle weakness and feels like she has to lay on the floor. This has happened now at least 3 times that I know of.

My mom is addicted to benzodiazepines but these episodes appear to be unrelated (as in they don’t happen when she takes them). My mom is also on the antidepressants bupropion and venlafaxine (wellbutrin and effexor). I am in school studying pharmacy and I know that her individual dose of effexor could be enough to cause serotonin syndrome. I was not happy when her doctor added wellbutrin to her regimen, and I actually fought her on it but obviously lost. I am very concerned for my mom. These episodes, if they are indeed SS, would be mild… are they just going to get worse until it’s fatal? I admit that I don’t know much about serotonin syndrome itself. Do you think this is what it sounds like? And how do I help my mom? I have called the paramedics and she refuses to go to the hospital because when they get to the house she usually has started feeling better.