Although I didn't experience the sense of being out of breath, there were times in peri that around 4 or 5:00 p.m., I would utterly crash! Sometimes I would start supper, turn off the burners on the stove, go lie down on the couch, and start again later if I
could! Sometimes hub would have to finish for me. The fatigue was brutal!
And a couple of times, I served the family and then literally (yes I swear I did this) lay my head down on the dining room table while others ate. Why didn't this tell me something!!!?

Like - maybe it wasn't necessary that I should be the cook for everyone every night? (Kids were living with us at the time.)
Don't know what it was about that time of late-day, but that's when it would hit.
The breathlessness - could you be anemic? There are times my blood count has gotten low (due to heavy periods), and there's been a lot of lightheadedness. Now that I'm post, this is no longer an issue.
((HUGS)) - hope it passes soon.
JJ