Hello,
The most common side effects of sertraline are sleepiness, nervousness,
insomnia, dizziness, nausea and upset stomach. So your giddiness may be a side effect of the drug. Consult your doctor for changing the antidepressant or timing the antidepressant so that it does not cause giddiness like you may take the drug 2 hours after meals or get a PPI inhibitor like Omeprazole added to your prescription drugs.