High Progesterone on Day 3

I had a baseline (day 3) ultrasound this week. Because my lining was very thick, the dr. ordered hcg and progesterone bloodwork to confirm that I was not pregnant before we proceed with femara, injectables, and timed intercourse. I was not pregnant. However, my progesterone level was 88. What could cause this to be so high? Should I be concerned? Additional info: I was on clomid for 6 months during which time my progesterone levels varied from 5 - 35+, but never higher than 40. I had several follicles in each ovary.