Infertility/ thin endomet. Hmg for me?

I have been undergoing infertility treatment since last couple of months. Doctor began with clomiphene 100 mg and then added hmg 75 mg (menogon). Due to irregular and prolonged bleeding during stimulation cycle, I had hysteroscopy. A few polyps were found and were removed. The tb pcr and hpe all came negative. Mantoux and tb gold are all negative. Again began treatment with clomiphene and hmg. I again had problem with the endometrium growing less (6.9 with estradiol supplements). This cycle began straight with fsh 150 iu for 4 days then hmg 150 iu. Lining was growing at good rate first few days then still at 5.4 then 5.8. Now 6mm with estradiol supplementation,iui is in two days. 2 big follicles(few more were growing but stopped at 13 mm or less). Estrogen at mid cycle is 750 indicating healthy eggs. Please let me know why my endometrium is not growing. I have symptoms of pcos but low LH. Is there any other reason except tb for it to not grow. Is fsh only better than hmg for me?