-0.75 dioptre spherical is your prescription as you have mentioned .
This is a myopic refractive error
in which your distant vision will be hazy without spectacles .
Not wearing specs may give u headache but not everybody suffers that .
you can even remove them at times when haziness does not bother you much if that doesnot give you headache.
These refractive errors may sometimes change gradually so annual eye examination for the refractive status of your eye is recommended.
contact lenses may be tried if u r comfortable in maintaining them.
As far as diet is concerned there is nothing specific ,yes replace junk food with fresh fruits or veggies for the overall health of your eyes.
Having this refractive error should not be a cause for any amount of anxiety