Live in austin tx. fell off raft in lake austin and head went under. scared of n fowleri. day 3 only have mild ache in sinus around nose. no other sym?

Does not sound: like N. fowleri infection which causes primary amebic meningoencephalitis which destroys brain tissue. Sx's usually begin within 2 to 15 days of exposure & may include sudden fever, severe headache, neck stiffness, nausea / vomiting, light sensitivity, feeling tired, confusion, loss of balance, hallucinations, seizures & death. You would be quite ill if you had N fowleri infection.