Talk to Gynecologist on TTC

salam doctor RUKHSANA TARIQ. i had a high fsh which was treated. got my fsh level down to 9.2. then i was on Ovulation induction treatment. i was on femara (letrozole) 5mg CD3-7. followed by follicular tracking thn 0n 9th and 10th day was given menotrophin inj 75 iu. on 11th day hcg trigger shot of 10000 iu was given. i did ovulate. 2 matured follicles on 11th day. but didnt conceive. endometrieum lining was perfect. was taking duphastophon 20 mg daily from day 13-25. now on this cycle the doctor gave me clomid which i am taking. my question is what are the reasons of not conceiving when everything was on spot? is the doctors decision right of putting me on clomid after 1 unsuccessful cycle of letrozole.? JazakaAllah