The prescription power changes every few months. It’s possible that your power gets a little stronger and you should have your eyes examined again. Usually I go to see my optician once a year.
You might have got the lens with the wrong prescription. You should see clear if there is nothing wrong. If I were you, I would go to check my lens and eyes without hesitation as soon as possible.
I recommend you to take a break if you work a lot on computers or cell phones. Your vision will become weaker if your eyes get exhausted. Normally you will be fine when you have enough rest.