Hello, 
I'm very sorry for a headache you are experiencing. 
To me, it's related to stomach problems you faced 2 days ago. If it was from food 
poisoning (which I think it was not), you should not have had a high temperature. To me, it was a bowel infection from any acute virus. 
Take antacids to stabilize stomach pH; probiotics to stabilize intestinal flora. Continue taking 
ciprofloxacin for at least 5 days. 
With regards to your recent 
severe headache, it is due to :
- loss of fluids and electrolytes after getting a high temperature and stomach sickness (
dehydration)
- should monitor your blood pressure to see if severe oscillations
- should monitor blood sugar levels to rule out possible 
hypoglycemia from not feeding well during these days of stomach sickness.
I think you should go to the ER or consult with your physician further and to get a few diagnostic tests run. 
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Albana Sejdini, 
General & Family Physician