Another visit to Dr Yang in the army hospital last Tuesday led to him suggesting I stop virtually all the medicines I've been taking for various ailments, and see how my headaches and dizziness are affected. So far, I've felt no worse. The all-day headaches are now just an occasional light-headedness, which is an improvement of sorts.
Worse news from home though, with my Dad finding out that a recently removed tumour was cancerous. None of the doctors thought it would be, so it was quite a shock for him and all the family. They will monitor him closely now, and don't think it's likely to spread. But still, not nice.