Prescribed Clomid For Follicle Growth. Suggested IUI. Reports Normal. Why Is Follicle Size Not Growing?

Hello Doctor I am 29 year old, going through the fertility treatment. All Hormone test, thyroid test, PCOS test, all seems to be normal. Semen analysis of my husband also shows all normal. Doctor prescribed me 100mg clomid from day 2 to 6 day. but the follicle size is not at all growing, till day 18. after 18th day the follicle size starts growing all of sudden 3-4 mm a day. And on day 21st follicle size became 24mm, My doctor then injected me with injection (I dont remember the name) , but that was for ovulation to occur then on 23rd day I ovulated(As per sonography reports, one follicle from my right ovary got ruptured). for continuous 3 days i had relation, but still I got my period on day 32 of my mensuration cycle. My doctor is now prescribing me to go for IUI. My concern are: 1. Why the follicle size is not growing when all my reports are normal? 2. why even after taking clomid the size follicle is not growing normally(1- 1.5mm a day) ? 3. Is my treatment is going on right direction? 4. Should I go for IUI? will it be helpful Please suggest Thanks