I'm on my first round of Letrazole (2.5mg) and I'm 11 dpo. This morning I woke up with pretty strong low back pain that has been getting worse as the day has progressed. I don't normally get low back pain as a PMS symptom, and the sore boobs that I normally have are strangely absent. If you have taken Letrazole/Femara before, has it given you low back pain as a side effect? I don't want to get too excited about it as a pregnancy symptom because I've been let down with that before. Any insights would be helpful!