Have you seen a therapist for it?
While the pill doesn't directly cause depression, it can emphasise those feelings and you may experience changes in your mood. It would be wise to see a therapist who can help guide you through it.
Keep in mind that you're going to go through a new adjustment phase (3-6 months) now that you've restarted taking the pill. Unfortunately sometimes you may need to try different pills until you find the right dosage that works for you.