Might be something different. Might not be.
Usually mild symptomatic hypoglycemia is characterized by ravenous hunger, shakiness, mild sweating for no reason, mild mood irritation, distractibility.
I’ve experienced the foggy-headed thing after a very large meal post-workout and it anything it feels like I need a nap. Might be more general fatigue related. “Rest and digest” signaling is elevated the post-prandial window.
If the experience is enhanced by increasing size of post-workout meal, it’s the latter.
If the experience is enhanced or changed in quality (ie. you get hungry/shaky) by decreasing size of post-workout meal, it’s the former.