I'm sorry to hear you're having trouble. I had similar issues until my doctor put me on a mood stabilizer. I'm not bipolar, but my depression fights back heavily against the medication. Even with the maximum dose of antidepressants, I was still crashing into horrible depression once or twice a day, and it lasted a minimum of 2 hours each time. I asked my doctor about a mood stabilizer, and he put me on Lamictal / Lamotrigine. That straightened me up. I'm fine now, but last winter was beyond horrible. Even if you're not really bipolar, a mood stabilizer can still help, and may be just what you need if your mood is still very unstable even with antidepressants.
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Heart of the guardian, way of the warden, path of the exile.