If your DHEA is also low (not speaking of DHEA-S) as well as your progesterone, maybe you should get your pregnenolone levels tested too. Progesterone cream is not inexpensive; pregnenolone is rather inexpensive.
However if you have other problems such as heavy metals you could bet that your body won't make all of those conversions as well as a healthy person can.
A close female friend who apparently has a heavy metal problem has responded nicely to pregnenolone, progesterone cream, and also a very small dose of hydrocortisone (cortisol) medication.