Thanks for choosing health care magic for posting your query.
I have gone through your question in detail and I can understand what you are going through.
I guess you were drunk when you had water and you could have aspirated it. That could have led to your gasping for breath. No oxygen
to the brain can then lead to headache.
Now its a rare possibility but still it seems likely in your case. You dont need to worry if you are fine now. Otherwise it would be wise to get an MRI
scan of the brain.
Hope I am able to answer your concerns.
If you have any further query, I would be glad to help you.
In future if you wish to contact me directly, you can use the below mentioned link:
Wish you good health,
Dr. Srikanth Reddy M.D.