Could Vaginal Spotting Post IUI Be The Symptom Of Miscarriage?

Hello. I am on progesterone after IUI, today is my day 11 after procedure and I feel cramp on the right side and now spotting. I am supposed to go for pregnancy blood work in 2 days because I was told that I can not get period while on progesterone even if I was not pregnant. Should I be concerned of miscarriage or is consider this spotting sign of period, and not even do blood work? Thank you. D