Welcome to HCM
We understand your concerns
You did not mention you age and about any other health complaints you might have. Your blood pressure and sugar level in blood along with sodium and could be the reason. You should be aware that after heavy food body tends to take full rest so that maximum energy is used for digestion. Are you sure that it was dizziness
or have you slept unknowingly? I am not suggesting but it could be a possibility. Anyway consult a general physician and check your vitals.
Get well soon.