It's not clear if you're saying the engine cranked slow or if it took more than the usual amount of cranking time to start the engine.

Two weeks of sitting, especially if the battery is weak, could cause slow cranking. Sitting for that period should not have much effect on cranking time, but very old fuel can loose the light components at the top of the distillation curve and cause excess cranking time or flooding due to the lowered vapor pressure.

I store my car about six months a year (fill with fresh fuel just prior to storage), and when I go to retrieve it and install a freshly charge battery it starts about the same as if it has only been sitting a few days.

Duke