Anyone else experience this?

Had my last induced period Sept 17-20th. So I’m supposed to start my period anytime soon right???

(Background- my RE found I have a full septate and need to get surgery to remove)

Anyways my RE had me come in for an ultrasound on Monday and she found a 14 mm follicle!! She was like “that’s strange..” I went in yesterday to check and it was now 19 mm! I haven’t taken any letrozole. They tested my blood hormones and I have an LH surge! I’m so upset that I have to do this surgery but my RE also explained she doesn’t want me to experience any type of unsuccessful pregnancy 😓 I’m so confused on what my body is doing!