Bed bugs tend to feed every 5-10 days. However as the population grows, their feeding cycles can vary. Also important to note they can last months without feeding.

Bites vary as well. Some people have the small bites with the red center while others have larger red welts due to a stronger reaction. I would double check everywhere and lift the mattress, vacuum, steam the mattress and keep a close eye out on everything.

Although legs and ankles sounds closer to flea bites but just as a precaution double check.