What Causes Tremors In Body And Legs?

Im a 22yr old female, I get tremors In my whole body, but mainly my legs. The neurologist says it's hyper-reflexia which I had once when I took an overdose of medication. It's been progressing for about 2 years now. Some days I feel fine, and other days I feel very crappy, everywhere! It's hard to explain the feeling. All my muscles feel funny and I shake lots. On occasion I shake at night violently and my partner wakes up and tries to wake me. I feel as though I have lost some sense of coordination and sometimes my mind will go blank and I forget where I am or what I'm doing. I had an MRI of my brain but it came up normal. I'm going to get an MRI of my spine soon but I'm afraid it will be normal too! Sometimes I wonder if I an just going crazy. Any ideas?