It really is! I have been taking the Diamox for about 7 weeks now, the first three were terrible, the next three were great, but last week all my symptoms returned. My morning headaches were gone, the postural headaches stuck around, the pain behind my eyes lessened, my nasal airways opened, pulsatile tinnitus was at a minimum, it even reduced my crazy POTS heart rate and breathlessness. It was amazing, I even managed a real walk in the countryside. Last week that all reversed and I’m back literally feeling the exact same way I did before I took the Diamox. I don’t know what my body is doing. I wanted to stop the the medication but my GP hasn’t a clue what Diamox is and said she wants me to continue and she will write a letter to neurology who already signed me off, but she doesn’t expect they will reply. My GP and I are clueless. Are you from the UK Barbara?