a. I am feeling extremely sleepy.
b. I am feeling extremely tired.
c, I am feeling exhausted.
d. I am overcome by fatigue.
Are the above sentences the same in meanings that are interchangeable?
One can be sleepy without being particularly tired; after a nice meal, sitting in the sun...Zzzzzzz* )
Completely tired = exhausted, and fatigue is very similar, the last 3 sentences are largely interchangeable, simply different degrees of weariness.