Why Do I Feel Light Headedness And Mild Pressure In My Head?

hello.. For the last 5 or 6 weeks, I have been feeling a combination of light headeness and mild pressure in my head (front area) in addition to strain and watery eyes. There is no pain or loss of equilibrium. More recently, the light headedness starts within 10 minutes of waking up and the eye strain within half an hour of being in front of my computer screen at work. On weekends (when I do not look at screens at all), the light headedness is less severe and may be absent. I do take a blood pressure medecine as my reading are relatively high (typically 135/900). I am 40 yrs old and I weigh around 80kg.