Contact lens prescription vs gles prescription?

I wear contact lens's. I am nearsighted so i cant see far. my contact prescription is -1.75 in each eye. the doc also wrote me a prescription for gles. I have pink eye and was prescribed these drops so i cant wear my contacts for a week so i had to go and get gles. i noticed that the prescription for the gles show -2.25 in each eye although the contact prescription is -1.75. I asked the doc and she said they are 2 different prescriptions and this is normal. when i went to the eyegl store, i also asked them and they agreed that it seems right. they said that if the contact prescription was -1.75 than this prescription for -2.25 on gles is right. I havent worn glasses in year. they are making me see good but im a bit dizzy fromt hem. do I just have to get used to them? do you think the prescription is wrong? They sharpen my vision yes but i get a bit dizzy. it hasnt even been a full daythat i have had them. also keep in mind i do have pink eye right now.