I am sorry to hear about this concern.
Most of these flea medications are tested at many times the recommended dose to understand their toxicity profile. This is clearly an overdose for your little one, but unless she is exhibiting symptoms of illness, you are in good shape.
My primary concerns with Trifexis would be vomiting, diarrhea, loss of appetite.
I wouldn't expect seizures or tremors unless quite a bit more was ingested, or the pet simply was hypersensitive to the drug.
Of course, if you do observe any illness or she is truly having a persistent tremor, that is well worth a ER vet visit for supportive care.
Feels hot? You can take a rectal temperature with any digital thermometer. If over 103.0 when at rest, that would be worrisome and also warrant an ER vet visit.
Hope that information helps!