Feeling Dizzy after drinking water running twice a week

I am 40, 155lbs. I have been running(jogging) since couple of weeks 2 or 3 days per week. I am running about 3 miles outside(not in gym) sometimes in morning sometimes in evening. But since couple of days I am feeling dizzy immediately after drinking water. I am drinking a small glass water every 15-20 minutes. After some time I am not feeling that sickness(dizzyness). I am also feeling dizzy before I get hungry and specially in morning it is a lot. After eating breakfast I am not getting that dizzy feeling. During Lunch time again I get dizzy feeling. I had health checkup done couple of months back and BP, SUGAR are normal. Do I have a low Blood Pressure or is it something I need to check up with a doctor? Do I need to stop running for couple of weeks and see the results?

Thanks