This could be a vascular problem such as pending onset of a migraine-like condition without going all the way through to the headache. This can be caused by stress, not eating before activity, allergies to food, all sorts of things. Basically, the blood vessels constrict, and then as the system relaxes the ones nearest the brain open up first while the ones at the extremities stay constricted for a longer period of time. This pushes a lot of blood near the head until the vessels at the extremities open up, evening the flow. Normally, caffeine is a treatment for this, but people react to caffeine differently. Personally, I don't see the point of caffeinated drinks, I think you should learn to rely on nutrients and will, but obviously a lot of people use them to extend their workouts. Maybe you're just starting back into it too quickly.
Try and avoid doing too much crunches or lifting heavily when working out. Make some carrot juice or take some carrot sticks with you and eat them be4 you workout. If the blurriness is still there, you need to check your eyes.
Update. The dizzyness as a whole has stopped. The lessened vision has on the other hand remained. I got a general check up in the emergency room, heart was fine, and the CT scan of my head showed nothing out of the ordinary. Whatever caused my vision to blur whilst exercising did not go back to normal, perhaps it were only my eyes that were effected. Reading from a distance has become more blurred than usual, I wouldnt say there is a sensitivity to light in a severe case, but focusing on my laptop for extended periods of time at night (Where light is emanating more directly from it.) is becoming kind of a struggle.
You were simply dehydrated, I cannot believe the ER docs didn't clue into that, oh wait, yes I can! The high levels of caffeine dehydrated you pre-workout, and without water to rehydrate you during, you got extremely dehydrated. Don't take it easy on your workout, drink water before, during and after. Has happened to me many times in life. Your fine, it's your body's way of telling you it needs more fuel to function. Fuel=water :)
Caffeine overdoses are similar as well