12.5 mg Zoloft every other day?

Unfortunately, many medications come with side effects dizziness being very common with Zoloft:
"Nervous system
"Very common (10% or more of users): Headache (up to 22%), somnolence (up to 13%), dizziness (up to 12%),"
These side effects generally resolve within a few days to a week or so and they get better every day.
As for your dosing schedule, as Daisy has said, it should only be changed by your doctor:
"Take Zoloft exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not take this medicine in larger or smaller amounts or for longer than recommended."
Let her/him know about the dizziness and perhaps your schedule could be temporarily changed until your metabolism adjusts to the medication.
Best regards and I hope you're feeling better quickly.

Hi temp ... for that question you really have to ask your doctor or pharmacist. Sorry I am not allowed to answer stuff like that because I am not a doctor. Hope it works out for you and you feel better. Let us know ... good luck