Sever Fatigue and feeling out of it?

It is definitely something to see your doctor over. It could be something chemically wrong with your brain or even may be something physically wrong. Your doctor will be able to run tests and check everything out. Do you often get chilly and then suddenly sweaty out of nowhere? If the answer is yes, there may be a problem with your thyroid. Only blood tests can rule this out. Also, if you're getting shaky out of nowhere, it may also indicate bipolar depression or a neurological issue. Either way, it is best to go to your doctor to figure out exactly what is wrong so that you and your doctor, together, can fix it.