Cardi was walking through JFK Airport in NYC Thursday night looking kinda down and exhausted while talking on her phone. Girl was still rocking her Balenciaga, though.

You can understand why she might be feeling run down -- she's been on the go almost nonstop since the breakup -- performing a bunch of shows, while also dealing with all the drama involving her estranged husband. Traveling during the holidays can't help either.

We broke the story ... Offset wants to spend Christmas with Cardi and their baby girl, Kulture, and hopes to bring lots of presents for his girls to help smooth things over. We're told Cardi hasn't decided yet whether or not to allow it.

Offset's made it crystal clear he wants his wife back, but so far Cardi's standing her ground.