Wondering why I’m not getting pregnant

My husband and I have 4 kids all boys. our youngest is 1 years old. We are trying for our 5th baby! and last hopefully for a girl! My doctor gave me that go ahead 6 months ago. I have never had problems getting pregnant in the past. We did have a very early miscarriage in July I was 4 weeks. We always time intercourse with ovulation and still nothing! My doctor just put me on clomid I have take it Cycle day 3-7. We are hoping it works! I am overweight but I’ve been overweight with all of my kids. I just don’t know what could be stopping us from having one more. Here is my bbt chart. Temp dipped this morning so I know I didn’t get pregnant this cycle.