TTC Supplements

Hi ladies! So a little history on me: I'm 38 and currently starting cycle 10 ttc #3. I have been using opks and bbts to track my cycle and take prenatal vitamins. I have a 10-11 day luteal phase, which my obgyn seems to think is ok but I'm concerned. I can't switch obgyns because I work for a hospital system that's insurance policy really only covers you seeing its own docs and they just lost all but my obgyn on my side of town. I want an obgyn that is close to me because I have suffered from Hyperemesis Gravidarum with every pregnancy (I've been pregnant 4 times but only 2 of my pregnancies made it to term). HG is incredibly hard on my body and I need an obgyn I can get to easily. I am looking for recommendations on supplements to take that could lengthen my luteal phase and/or help me conceive. Thank you so much in advance!