Prometrium for perimenopause - regular vs. extended release

Late 30sF. I FINALLY convinced my doctor to let me try Prometrium after several other medications (wellbutrin, deblitane, effexor, zoloft, etc). YMMV, but it has helped a lot with night sweats, mood, and hot flashes. 100mg/1x a day. I have noticed that I get VERY tired right after taking it. I could get a lower dosage compounded (50? 75?), or I could get an extended release formulation. Has anyone tried extended release?