What Causes Headache,dizziness And Nausea?

Hi, I have had a continual headache for approximately 2 weeks now and have lad lower back pain for a week or so. I feel dizzy, my co-ordination is off, and am feeling nauseous at times. I have had bloods done which have come back normal and have another appointment next week with a GP. I have a history of rhinitus and am awaiting an appointment with ENT, but the headaches a new thing, never been a headache person until the last year or so off and on. Generally feel quite spaced out, can't seem to concentrate on things at work and feel unsteady.