Worried parent: Blaming myself for baby dropping in percentile for head circumference

My 5 month old baby has mostly been quite happy and healthy apart from when she gets overtired. However, for the past two months, I found out she has dropped in percentiles for her head circumference. It steadily dropped from 50th percentile in her 3rd month, then 25th in the 4th, and now she's in the 10th percentile for head circumference. Will be meeting a paediatrician soon but I can't help blaming myself over this cause there were times where I accidentally dropped or hit my newborn's head. Felt super guilty whenever that happened but I checked for symptoms of head trauma in the next 24 hours of each incident and she acted completely fine and her soft spot was normal. However now that I found out that her head growth is slowing down from average, I can't help but overthink things.

Came here to vent and maybe get some solidarity? I feel so guilty and worried. Did any of you experience this as well and your babies turned out fine? Need some reassurance before I meet up with a paediatrician.