When we see sunlight, the brain makes a peptide called by two different sets of researchers either hypocretin or orexin. Low levels of this peptide can cause cataplexy, which could be what you experienced. I suggest you google these terms and see if they seem to apply. If we avoid the sun, we can supplement with vitamin D3 to replace what we should normally make in our skin; but I don't know of any way to increase hypocretin levels without direct sun exposure.

Kind regards.