Cluster Aprocine Microcysts-have questions about pathology

I had a tiny lump I found and had a 3D mammogram and ultrasound done at a breast specialist yesterday. The look of it was benign, but it was mostly solid with some areas of fluid. Flat and wider than tall (all the things they told me they believed were good things). She said we could follow up in 6 months, or we could biopsy to be certain we didn't need to be concerned. I chose the biopsy and she performed it right there with ultrasound guided vacuum assisted biopsy. They expected results tomorrow, but they actually just called me and told me it was good news and what was found in the pathology was a "cluster of aprocine microcysts". She's said it was completely benign and no need to follow up, just continue with yearly mammograms. I'm 37, so typically we wouldn't have begun those for a few years, but this lump I found just started the process early. They said it was solid, but then microcysts would be fluid right? There was "flow" which was something I didn't understand when she mentioned it. I'm no expert but was hoping someone else could help me understand how a cyst would be solid.

I'm a highly anxious person and this has scared me so much. While two drs said it likely was benign and I should just follow up in 6 months, I pushed for biopsy and now even though she said it was benign I am worried about missing something. I have a call in to talk with them again just to ask more questions, but just wondering if it sounds like I'm being ridiculous with worry for nothing and just need to trust the good report. Again, I have high anxiety that I have just begun meds for, so this anxiety is playing games with my head. Wondering if I should be following up sooner than a year or if I'm being paranoid because of the scare.