unexplainable headache pain

First of all i've been having this off and on for the last 13 yrs and i'm 21. I remember the first time i had it was when i was in 2nd grade. I really need help, i don't know this is just headache pain.

Anyways, the pain starts with either my left or right eye and i can tell which side of my body will be effected. If my left eye than my right side of the body will get numb and vice versa. when the pain starts, i don't feel anything but i can see black spots when looking or trying to concentrate on looking a something. for example if i was to read "hello" part of the hello would be blacked out like it was never there. and then my eye, depending on which one the black spot is, starts to hard. The pain in the eye feels like the after pain after looking into the flashlight. within mins after that my side depending on which eyes it effects, will get numb. after that, i feel like throwing up, and i do, then my head. There's this sharp pain just pounding on and off..it also feels like my head's gonna explore
and than it stays for like 4-5 hrs. i really don't know what's going on with my body and my head...

if anyone can help, let me know.

Thanks.