Why can’t I get pregnant?

First off I want to say I know you ain’t a doctor and Please no rude comments! I’m not sure what is going on. My husband and have have 10 kids between the two of us from a previous relationship. my husband is a lawyer so all of our children is well taken care of We are trying for our second one together! We have a 9 month old together. We want to try for a girl. We have been trying since our youngest son was 3 months old. I know that they say not to try until 18 months but I want to be done having kids by 35 years old. I am 34 years old now. I ovulate every month we always time intercourse with ovulation. I did however got pregnant in July but it was a chemical pregnancy.This cycle is my first medication clomid cycle I take it day 3-7 and 100mgs. I’m not sure why I’m not getting pregnant if I’m ovulating every month and my husband and I tests are normal. My obgyn said to keep trying. I am on metformin to help me lose weight. He said i don’t have PCOS.