I can only speak from experience, and so this is based on what I know from what has happened to me. Yes, both of those medications stopped working for me, and rather quickly at that. In fact, they had a rebound effect so that the issue that creates sleep disturbances for me (Restless Leg Syndrome (RLS) would intensify, and when that happened, I would get virtually 1 - 1 1/2 hours sleep per night. I'm not sure about the heart pounding, but I've taken medications for fibromyalgia that created that symptom for me, so it might not hurt to discuss that with your doctor. Is it possible that the anti-anxiety drugs are now creating an increase in your anxiety, and could that lead to your heart pounding? I know when I'm anxious, my heart pounds, and I can experience dizziness and a headache as well. Again, maybe a change in medicine would help you.