Progesterone

Does anyone have experience with getting their progesterone levels checked? My Dr. Put orders in and told me to to to lab on day 22 to 24 or something like that. But the thing is, after my miscarriage, my 2nd period (after miscarriage) was wonky so I'm not sure when day 1 starts. My period was 5 days early it was heavy then light and short then I was bleeding again 2 days later for like 6 days straight and it was heavy now light. So no idea when day 1 actually started. We would like to try for baby again. What if I do the test at the wrong time and it shows my level is normal when it's not. I'm so confused on when to do this progesterone test. I wish she would just prescribe me medication. Thanks ladies.