Is my spherical correction too strong?

I have worn contact lenses or glasses most of my life, and every test I have had done by the eye doctor I consistently had a -.75 spherical correction in both eyes. On my most recent eye exam I had, I was getting some updated lenses to correct for my astigmatism (which my contact lenses already were doing). I have been trying to get used to the astigmatism correction, in which things feel about normal now, but I have a feeling I can't get rid of, as if my eyes are over-worked. To explain, if I roll my eyes to one side of my head in any direction I can feel a lot of pressure in that area.

I noticed that on this new prescription the Doc gave me -1.25 for a spherical correction. I never noticed blurry vision using -.75, so I am not sure why he gave me such a bump in power, but could this be causing my slight headaches/eye-aches? Or would this have any negative effect at all in my vision? (I work close up at a computer majority of my days at work and with school.)

Thanks!

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