I Had Day 3 Embryos Transferred On Tuesday. Since Then

I had day 3 embryos transferred on Tuesday. Since then I have been extremely exhausted! I can barely function. At first I thought it was because of the valium they had me take before the procedure but now that I am 3 days post procedure obviously it is something else. Is this just caused by the progestrone I'm taking? I feel the same way I felt when I pregnant last year before my miscarriage.