Glad you made it alright, with a lesson learned! That sounds like a classic foot entrapment, which is probably one of the more common water accidents around current. And also common with 'tubers in the summer.

When kayaking, we teach people not to stand in more than knee deep water, if they're coming back from an unintentional swim. Also while you're swimming, keep flat, whole body near the surface, and feet first so you can push off obstacles as needed.

All that gear is worth it.
Jason