Terrible sweating like that can come after eating, if you are diabetic.
Consumption of less than fresh fish/seafood can also do it...this is a histamine
reaction. Tomato sauces, monosodium glutamate --food additive-- may do it.

Drugs--- opiates are big offenders. Certain other drugs like Strattera, or Effexor or Cymbalta will do it. Did you have GI disturbance? There is a tumor called carcinoid, which puts out large amounts of serotonin and that effect is similar to what you describe, but there is usually a GI cramping/nausea with it.

Some tumors of the lung secrete biogenic amines like that. Doctors know how to test for them. These types of symptoms precede discovery of the tumor.
So I'd report this to your doctor.