Eye power 0. 5 cylindrical after age.

Hi, i am 26 years old and have never had any vision problems. I work most of the day in front of a computer. For the last one week i realised i was seeing a bit of doubling vertically and my eyes were paining a bit especially late at night, the doubling was especially visible in texts and horizontal lines. I went to the eye hospital the next day and saw a doctor. He said i had -0.50 cylindrical power 180 degree in both eyes and prescribed a glass. I took the glass and the glass definitely makes things a lot more sharper. Since then i was reading online that adult vision from 19-40 doesn't really change and I got a bit scared since I am 26 and have never had any eye problems before this. Is what's happening to me normal or is this something i should be considered about and go to the doctor again? Thanks in advance for any help any of the doctors on this site can provide.