@Avalon—you have received manifold advice and support on this forum; yet, you seem unwilling to take control over your situation. You’re obviously a bright fellow, evidenced by your weighty reading choices, but you resist improving your situation. You may be agoraphobic.
How long has it been since you’ve had bloodwork done? Have you had a full cardiac work-up? Are you fearful of the results and possible diagnosis? All of that is understandable. But, unless you resolve to get out of your sanctum and spend a day with clinicians to find out what your current medical situation is, you’ll continue to deteriorate. You have the power to make tomorrow the beginning of a better life.