Very slow today

Another 4.8 miles today from home to office, but 66'18'. I did not run yesterday, but had some upper body weight training. I am ready for today's run. I think it would be an easy run and should have finished within an hour. Could it be because of lack of carbon hydride intake from last night? I did not eat any carbonhydride food other than a peach after 6:00pm. I feel I was getting tired very easily today, although I drank gatoraid when running.