So i was playing OB and got in a real tough spot so I start downing potions when suddenly a message pops up saying that I can't use anymore potions at this time?

On Xbox without the DLC's

This is SOP. Nothing to worry about. Not game mechanic wise in any case. Heh.

-Decrepit-

What is SOP? I haven't played OB for a while so I can't remember.

SOP = standard operating procedure

-Decrepit-

You can have up to four potions active at once. Same with poisons (four) active at once on your foes.

There is a silly glitch/workaround to exceed four, but if you need more than four, your character should consider other employment.