If your peak flow is within normal limits & the rescue inhaler does not help, then most likely it isn't asthma. W/asthma you would see decreased peak flow rate & relief w/inhaler. There are many things that can cause your symptoms... from sinus infection (headache, lightheadedness) to blood pressure or perhaps thyroid. Since you do not have insurance, try the free readings of BP at you local pharmacies. Many towns have Family Health Clinics which charges you by your income. Good luck and hope you feel better soon.
Info meant as med info only & not as med advice.