To be honest, it sounds more like possible withdrawal symptoms from going off the Lortab cold turkey. What other symptoms are you having? Muscle aches? Sweating/Chills? Sneezing? Diarrhea? Nausea and/or vomiting? Those are some common side effects of opiate w/d.
Serotonin syndrome is actually quite rare and almost always requires a pretty hefty dose of an SSRI like drug to trigger it. It's usually considered a medical emergency.
I would discuss all of the above with your doc.
Hope you're feeling better soon!
Symptoms:
Agitation or restlessness
Confusion
Rapid heart rate and high blood pressure
Dilated pupils
Loss of muscle coordination or twitching muscles
Heavy sweating
Diarrhea
Headache
Shivering
Goose bumps
Based on this, I would say, no. It is orthostatic hypotension which means your blood pressure drops suddenly when you get up too quickly. When it happens just bend over until it passes. It can be a side effect of some drugs but I didn't look up Prozac to see if it is a known side effect.
60-70mg per day by the way