I've Been having eye problems (blurred vision, slight double vision) that i went to see a doctor about, 2 months ago.

He said I have eye strain and gave me some glasses to read with, told me to come back 3 months later.

But Recently i also notice that when i lift weights, it gets worse.

I should also note that it strangely gets worse with the more protein i eat. I'm also urinating excessively. See here http://www.healthboards.com/boards/showthread.php?t=488649

Even after a light weight lifting session i'll get redness, itchyness and more blurrng.

What could this be? Thanks

Calling Dr. House.
Since I'm not a doctor, none of this might be of any value. First of all, I personally don't think there is any such thing as eye strain. I might grant somebody with strabismus a case of eye strain, but that's it. Just a bugaboo of mine.
If the visit to the doctor two months ago was your only one, you definitely need to go again, or to a different doctor. Have you been tested for diabetes? There are surprising connections between the kidneys and the eyes, but kidney disease that causes vision problems is fairly rare. Ditto for heart problems that cause vascular changes in the eyes. Then there is:
Uhthoff's Syndrome - A metabolic by-product of exercise, or an increase in body temperature causes a Reversible Conduction Block in a DeMyelinated Optic Nerve, resulting in the temporary loss or blurriness of Vision.

You need more medical tests IMO.