Legs collapsing

Twice now I have attempted to stand up only to have my legs collapse. The first time it was only my right leg and I fell trying to take my first step. The second time, I had no legs to stand on. Both times the ability to stand came back within 30 seconds or so, but weakness remains.

ER doc said my labs look good and sent me on my way. 😂

I just needed to know if it’s a POTS thing.