I'm having somewhat similar problems and I'm waiting on a reply to see if I should see a neurologist. I had blood tests done for magnesium, potassium, thyroid, calcium, and all that good stuff to see if it could be that but mine all came back normal. You should for sure have blood tests done and if it isn't some sort of deficiency then see a neurologist. That's what my doctor recommended.
Magnesium deficiency symptoms include nystagmas (uncontrolled eye movements), headaches, and stuttering. Physical and mental stress depletes magnesium.
have you gone to a doctor yet to have them check you out? the headaches, eye shaking/white background, lisp and stutter could be a result of seizures. when people think of seizures they think of basically passing out and start shaking nonstop but there are different types of seizures. you might want to go get checked by a neurologist, get an mri done, and see an eye doctor. stress could also be a factor, stress does cause headaches sometimes and other strange things could happen to your body. i am also 18 years old, pre-med college student so i know what kind of stress you are dealing with. i also suffer from daily migraines and have a brain tumor so i somewhat know how you feel. but go to a doctor, get checked and i hope all goes well (: