[i_like_black]

Have you ever had migraines? They're severe headaches that have a number of symptoms, including nausea and sensitivity to light, although some people also experience auditory and visual hallucinations. I'm mentioning this because you said you get headaches along with all these other things.

I know that for me, nearly ALL the things you mentioned, are migraine triggers. It may not be the case for you, but it's a possibility, especially if you find the headache to be somewhat debilitating.

I also found that cooling my forehead and sleeping were the best cures for me - painkillers add to my nausea.

So yeah. Just a suggestion, it could be migraines.
Do ask your parents if they can take you back to the doctor though, because clearly this stuff is causing you some amount of distress and so should be treated. Or at least, looked into more carefully to establish a cause.