What Causes Headaches And Numbness On Side Of Body?

hello. i sometimes get really bad headaches. they start off with my vision being impaired i guess? i can see but i cant at the same time, i don t know how to explain it. my vision isn t blurred im just unable to like see through most of my eye, especially if i try to focus on something. then my stomach gets really upset and i begin to get numbness on one side of my body (it usually changes sides) it starts off with my hands usually then spreads to half my face, half my tongue and then my leg. after that i throw up everything ive eaten or drunken. and after that its just a painful headache, i cant eat or drink anything (that includes water) or i throw up really violently, until im throwing up like gross nasty burning liquid (i assume stomach acid) and then i usually take some medicine and sleep for 6-10 hours and i wake up and feel better but my head still hurts slightly for days. this happens every couple of months. and lately my eyes have been pretty light sensitive. please help :(