Hi Yevette, Headaches come in all shapes and sizes and for many reasons — this secondary headache may not be pressure related, in fact. It could be a side effect of Diamox, or even due to your brain shifting position from the change in pressure. You are on a small dose, and I agree with your doctor that it would be a good idea to try another dose about 4 hours after taking your first dose.
If the headache goes away, you know what you’re dealing with! I hate to keep preaching this, but please make sure that someone is watching your electrolytes, OK? Gentle hugs…