African heat symptoms and conditions

I took doxy (100 mg a day) for approximately 12 months as a malaria prophylaxis. I experienced mild heartburn for the first month, vomited a couple of times until I learned I must eat a full meal first, and was very sensitive to the sun. After reading the other posts I now think I also experienced two other side effects: extreme lethargy and dizziness--at the time I thought it was due to African heat.