Malaria prophylaxis 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.

I have been taking doxycycline for 2 weeks (Malaria prophylaxis) now and have noticed some unfortunate side effects this week. I normally work out and feel great. Last Tuesday and today I felt absolutely wretched after my work out - ESPECIALLY today! I felt like I was having a heart attack. It started out with a bit of nausea and dizziness, light-headedness set in and by the time I got home I was so ill and my arms and legs were tingling all over. I lay down for a while and started to feel better. I still don't feel quite like myself. I've also noticed some heartburn. I had been taking zantac and stopped a couple of days ago - so my guess is I hadn't noticed it before because of this.