Hi,
Your spherical equivalent (refractive error) is -6.375 left and -6.75 right. Although within limits for the astigmatic component you are respectively 0.375 and 0.75 dioptres over for left and right eye.
Don't despair. It's more than likely that your vision is better than the the 6/6 cutoff with the Optometrists' prescription. Go back and ask him to recheck your vision with a combination of sphere and cylinder that does not exceed -6.0 dipotres. Although you will be slightly defocussed, given that you slightly exceed the limits, you should get 6/6. Record this as your refraction. Ensure he tests your vision in as bright a light as possible - constricts the pupil creating a vision sharpening pinhole effect.
If you still have problems I'd be very surprised if an Ophthalmologist examination, as per guidance, doesn't clear you as OK