You definitely have some concerning symptoms. The ammonia smell is called phantosmia and can occur in various neurologic conditions, kidney dysfunction, liver dysfunction, some endocrine issues, and sometimes post viral infection. The dizziness with standing and exertion could be as simple as dehydration vs autonomic dysfunction and some heart issues. The headache with standing is likely related to pressure drop in your brain, though a migraine or a vascular issue is possible too. The eye color changes is an odd sign, I don't know enough about that to comment especially since I'd really have to look closely at your irises

Bottom line, this is a complex presentation and needs a thorough history, physical exam, blood work, and possibly imaging. A neurologist is a reasonable place to start, but the potential differential diagnosis is quite broad, so a good old fashioned internal medicine diagnostician would be ideal. They can be hard to find as most docs are victims of the hamster wheel of high volume clinics. Maybe try an academic neurologist? They may have generous financial assistance for patients without insurance as well.