Thank you for posting your query.
Your symptoms could most probably be a result of migraine
with visual aura.
In this condition, the sufferer sees flashes of light or dots, etc in one half of vision (sometimes both sides also), this is called visual aura.
After a few minutes, this is followed by headache, which is often on one side of head (sometimes, whole head). Headache lasts for 4-72 hours, and may be accompanied with nausea
You should consult a neurologist
for evaluation and treatment.
Wishing you good health,
Dr Sudhir Kumar MD DM (Neurology)