I Have Been Getting Strange Headaches, What This Could Be ?

I've been getting these strange headaches lately. They're not like your ordinary headache. It's almost more of a lightheadedness feeling. It's really mild but very lingering. I have it pretty much all day, like a background thing. Usually I can ignore it but sometimes it gets worse and turns more into like a regular headache, sometimes with some very mild dizziness and nausea. I first started experiencing it maybe a few weeks ago, and it would come and go occasionally but over the last few days it has been more prevalent. none of this is very impairing to my everyday life or anything, it's just freaking me out. any ideas what this could be?