Small hard breast lump— 33 weeks pregnant

Two weeks ago I discovered a small hard breast lump on the right breast. It feels hard, smooth and immobile. I had an ultrasound on that breast 9 months ago for another lump that my doctor had found below my armpit that turned out out to be nothing so I wasn’t too concerned when I found this one. However, it is immobile, which makes me nervous so I just emailed my doctor’s office to make an appointment and have it examined.

Has anyone else experienced this? Trying not to worry too much but of course it is concerning!