I can barely see anything 20 cm away
For higher prescriptions Lenscrafters is good because they're quality pairs, last a good time, and you get free adjustments and things.
However, a prescription as low as that should be covered (as some people had already mentioned) at Walmart. I'd recommend popping by Campus Health and seeing if they have any suggestions. I understand about the exchange rate but since it doesn't always transfer over there's not much you can do about it except shop around. (30 AED keyboard cover < $10, but here it's 30 bucks.)
In the mean time the most important thing to do is not panic.
You'll worry and worry and feel like you can see less than you can.
I barely ever wear my glasses when I'm outside but knowing I have them makes me feel more secure. The minute I lose them or they break I feel as though I've lost a foot.
You've been in more lecture halls than me, Huzaifa, so I may be wrong but you could just move up until you find a pair you're happy with.
20 feet is fine, don't worry just yet
You'll be okay and the minute you find a pair of glasses you like (and I'd buy a backup. Always always always. They're like external hard drives - for the eyes
) you may even find you don't feel that reliant on them anyway.