What's the deal with my eyes being so sensitive to light these days?

Get it checked asap, random photosensitivity to the point of having to wear sunglasses at home isn't really something you would want to ignore.

Worst case scenarios:
Glaucoma
Migraine
Retinal detachment

Or it can just be that you have spent too much time in dark to go out.

I have the same problem. My aunt, who also has the same problem, tells me she was diagnosed with chronic low-grade migraine.

Protip: Use red sunglasses. They block out the painful spectrum. But you might have to go through a few pairs before you find one that doesn't make everything look yellow.