Serotonin Syndrome is very rare...and usually only seen in taking the max dosage of more than one SSRI for extended periods of time.
I am confident that all your results will come back as normal.
As far as your other concern it is probably a good thing for yo to be discontinuating the Abilify...as this is not typically an Rx to treat anxiety and mild to moderate depression...but a rather significant antipsychotic/mood management drug.
Use your coping skills to get you through this medication transition. Envisioning only a good outcome, since that will go a long way in ensuring it happens.
Keep up posted so we can keep you in support!
"Courage is not the abscence of fear, it is feeling afraid and doing it anyway!"
"Worrying does not empty tomorrow of its troubles...it empties today of its strength."
Corrie Ten Boom
Panic Syndrome recovery due to CBT