The postpartum woman should refrain from praying for 40 days unless her bleeding ends before, then she should do Ghusl and resume praying. If she sees any blood after 40 days, then most of the scholars say that she should not refrain from praying after forty days.

Your ‘umrah is valid, in sha Allah, and this discharge is not menses.

A spot of blood is not regarded as a period, because menses is blood that flows from the uterus, so it cannot be a mere spot. For more, please see the detailed answer.