This is a common fear, but antidepressants don't change your fundamental personality or who you are. Instead, they help lift the fog of depression so you can access parts of yourself that have been buried under symptoms. Many people report feeling more like themselves again once their medication starts working.
If you notice changes that don't feel right, that's important information to share with your doctor. Medication should help you feel more balanced and capable, not like a different person entirely.