I feel blah!!!?

I've been feeling lightheaded, with vertigo; lack of energy.I'm trying to eat right, and watching my wieght. It started on Sunday. The feelings of "blah"-ness come and go. I looked it up and it could be anything from CFS to diabetes. I'm going for bloodwork tomorrow. I'm sick and tired of being sick and tired!!! I'm a 40 y.o female with no prior health problems.