What Causes Vibration In Hands, Sweating And Dizziness?

ive been very weak lately. i have shaky hands, i sweat when its comfortable to everyone else. when i stand in heat i will almost pass out because i feel dizzy and light headed. i do sometimes have nausea but only after i eat. i had alot of blood work done but it has came out to be normal. my family doctor does not know what it going on. so then i went to the eye doctor because my eyes feel like a vibrating sensation. but they said everything was fine. Can you help me?