I found anything where I had to concentrate caused fatigue. When friends came to visit, I’d limit them to an hour, any longer - fatigue hit. I put it down to the brain having to rewire itself. Even now, 3 years on, I find background noise (music playing or too many people chatting) tiring as my brain seems to ‘fight’ which to listen to & I’m tired afterwards.
I can agree regarding the blood tests. I was on B12 quarterly injections prior to my stroke - told I didn’t need them afterwards. Following chest pains 1.5 years ago, I had 2 blood transfusions & an iron transfusion on the same day in hospital - low blood & iron levels which had caused the pain & also a different type of lethargy. Thankfully. I’m now on regular B12 jabs & iron tablets. From what I’ve read - it’s a side effect of the stroke & tablets we take that keep us alive!
Make sure you contact your GP for blood tests.
This is a time when you need to listen to body’s needs not yours.
At the gym, for any exercise I do, I do 3 sets of 10 repetitions with one minutes rest between each set of 10. I get the same amount of rest when moving to the next exercise. But I’m 20 months ahead of where you are right now, I had my stroke over 2 years ago.
So, why not try doing your exercises in sets of 10 with few minutes between each if you are doing more than one set. Rest for 10mins between each exercise by sitting down and just closing your eyes before moving on. Then take a nap when you’re done or again just 15mins where you sit down and close your eyes and just be! I still have a tendency to do that even when I’ve just pulled into a car park, just shut my eyes for 5 minutes 
Your brain needs that sleep time to process all that’s been taken in. So frequent naps are still the order of the day I’m afraid, it’s a must!