Based on your history your son is diagnosed with migraine for which he has been started on cyproheptadine
which is an antihistamine drugs used for prohylaxis in migraine.Since your child is still having headache he require higher studies like MR venogram brain to rule out other causes of headache as CT scan can miss minute changes in brain.Feeling of sickness or drowsiness can be due to cyproheptadine itself. Dizziness,Blurredvision,Constipation
,Dry,mouth,throat, or nose,Excitability,Nausea and Nervousness
are other side effects of drug .Nose bleeds are not associated with drug for which he need evaluation by ENT surgeon and treatment planned accordingly.He also need detail evaluation clinical and also to rule out chronic meningitis which can also produce sudden onset of headaches, vomiting, nausea, weight loss
,and tiredness Hope this help you.
Dr Sandhya ManorenjNeurologist
Hi Tech city Hyderabad