Slow Rise BBT after Trigger Shot?

I had a Clomid IUI this month and receieved a trigger shot on Day 12 and had IUI late Day 13. Im on Day 15 now and have only had .1 stair step temps up. I normally go up .5 or more the day after I ovulate. Any thoughts? Maybe progesterone taking a few days to register? I want to make sure I ovulated especially when spending that money!! I had 1 follicle at 23 mm. This is my 1st trigger shot and IUI. THANKS