What to do if I feel shaky all over body. Can this be als, Parkinson's or ms?

Also consider- You should consider these diagnoses instead- essential tremor, hyperthyroidism, and medication side effect. These are much more commonly the cause of a symptom like yours. Parkinsons normally causes symptoms of slow movement and rigidity, and a tremor at rest. MS normally causes weakness, numbness of difficulty with vision. ALS normally causes painless weakness and significant weight loss.
Tremors? Shaking over the body can be due to tremors, such as familial essential tremors, but may be seen in parkinson's, wilson's, and secondary to hyperthyroidism. Many medicines can also cause tremors such as asthma meds, depakote, amphetamines, etc. But an isolated tremor does not define als, ms or parkinson's unless other signs are present.