Well Recently I Have Been Feeling Really Tired As If

Well recently I have been feeling really tired as if I need something to boost my energy. I'm never like this . So iv also noticed I have been feeling as if I am about to pass out like uneasy. This happens more so if I bend over or stoop down and get back up. I notice I do feel better once I eat something then the symptoms return. I'm a 43 year old female. Non smoker , non drinker and do exercise moderately. I notice to I have some pressure up in my forehead and cheeks . MY blood pressure runs around 107/71 . This is normal for me. What may be going on?