Lump in breast postpartum

Hello,

This is my first time joining a forum and under less than ideal circumstances.

I had my baby through IVF in Oct. Shortly after I felt a lump in my right breast. I was told to massage this as they thought it would be a blocked duct. Weeks after and it was still there. It's firm, not very movable and doesn't hurt. It's smooth. At my 6 week postpartum check the doctor felt it, her facial reaction and her sudden tannoy for an urgent referral worried me. I have an appointment on Monday 14th. I'm terrified especially having just given birth. Any help or advice would be amazing x