Swollen/tingly ankle.

I woke up this morning with my right ankle swollen out of the blue. 37 weeks tomorrow, 3rd pregnancy-- never had a swollen ankle before. BP was fine at OB appointment yesterday.. I have had a mild headache over the past couple days- but I'm very prone to them. I guess my question is, at what point do you let OB know? Should I just wait till my appointment on Tuesday.. or if it starts to become overly uncomfortable? Thanks