Hi,
You have received some pretty good responses...You say you went to a Physician and that your blood tests were all normal...However, since your problem still exists, I wonder - Did you call your physician again to discuss what else it may be?
You say you "stopped taking your Lithium" 5 months ago...Was that the physician's suggestion? Or was that your own? And, if it was your own, does your physician know about this?
Perhaps you are not aware that it is not wise to suddenly discontinue medications, especially one so crucial to your overall well being, such as Lithium.
Your symptoms mirror many maladies, and it is difficult for any of us in this forum to make a proper diagnosis...However, the advice I would give is to see your physician, take care of this now before it worsens...You are being crippled by this "exhaustion" and it will not go away on its own...I believe that your perserverance will endure, and eventually you will find out the origin of your exhaustion, and low motivation.
You are very aware, I am sure - that your symptoms are classic signs of depression...So, please get the proper help, you are a young girl, you have many years ahead of you...Why not make the most of them by getting to the root of the problem, with proper diagnosis ( I am assuming due to the drug Lithium that you have been diagnosed by a physician)- and with the proper treatment, along with guidance and input you will lead a functional and well balanced life.
Go with a good friend, or family member, you need a support system in place to get you through this frustrating time in your life.
All my best to you...Good luck.