Not sure of your age, but have you gotten checked out by a physician? I’m not a physician, but IMHO Your fatigue and weakness point to an underlying medical issue that you should get checked out ASAP. Could be low thyroid or ?? Also don’t forget operating with a known medical issue may not be consistent with 14 CFR.
Highly recommend loss of license insurance also...
I have known many folks have lost their medical ceritification and transitioned to the training dept or flight office (i.e. Asst. Chief pilot, etc.). Also, have you considered going to the “dark side”? A good number of Fed positions do not require a FAA medical. If you lose your medical when employed by the Feds, you won’t lose your job.