Estrogen level

Hey ladies! Ok so I recently finished 100mg clomid days 5-9 and went in for my trigger shot. When they did my ultrasound (not too confident about the ultrasound tech) they said there was only 1 mature follicle and it only measured 18mm... I am super concerned that I'm not responding to clomid but then I got my estrogen level back and it was 607. According to glow, this level is indicative of 2 to 3 mature follicles. Does anyone know their estrogen level compared to the number of mature follicles they had? I haven't been able to find this information anywhere. Is it possible that she missed a follicle on the ultrasound?