Low progesterone

Been TTC for 4 mo. Now and had a 7 dpo prog level checked and it was 4.9. My OB said if it was above 3 I probably Ovulated, but didn't seem too concerned. I always have brown bleeding before/during/after my periods and they said that was normal. I'm going back to the office Wed to demand progesterone supplements. I've tried using creams after ovulation but it hasn't worked. Has anyone had similar levels and use progesterone successfully?