Letrozole now CD19 -???

I'm on cd19 I took Letrozole 2.5mg on CD5-9 and I still haven't gotten a positive ovulation test even the digital says low. From what my test looks like today when should I start to BD? I'm also really nauseous only food helps. My boobs are super sore and sensitive. I have body aches, headaches and I'm exhausted more than normal. I've also been experiencing pelvic pain in my ovary areas but still nothing has happened. Has anyone else had this experience with Letrozole cause I feel like it's slight flu like symptoms. I just feel like I'll never get my rainbow baby I'm feeling really defeated at the moment 😢😭💔.