You must be suffering from computer vision syndrome which is very common if you use computer for more than 2 hours on routine basis..
Next Steps
consult eye doctor & start using your glasses regularly even it is a minor number..
Health Tips
keep the brightness minimum of your laptop & mobile whenever you are using it..Follow 20-20-20 rule i.e.after 20 min of work on laptop you have to watch an object 20 feet away for 20 seconds...Blink your eyes properly... Avoid direct exposure of air of aircondition..Use a lubricating eye drop frequently after consultation with eye doctor..