Feeling very lightheaded & headache worried this is something serous?

Lightheaded/Headache: Lightheadedness and headache commonly occur together. A common cause of these together is simple dehydration. This can occur if you're not drinking enough fluids or you have some kind of illness where you could lose excessive fluids, like if you have vomiting or diarrhea. Acute blood loss can give same symptoms, but so could meninigitis. Best to be evaluated so you can get the right treatment.

Headache: When in doubt always check with your physician, urgent care or emergency room. Your physician can obtain an adequate history and perform an examination and determine. What tests are necessary. May need to check for anemia, thyroid disorder, hydration, poor sleep, migraines, etc. Hope you feel well soon.