15 month old hitting herself??

My 15 month old has started to hit herself whenever she gets frustrated or bang her head on toys idk where it came from it makes me so sad though & im worried 🥺

My adopted brother did that for a bit through toddler years but we could understand his behavioral issues because of what he went through in foster care & with his mom…

Idk if I did something wrong or if she just started the habit on her own, I have gone through depression struggles where every once in a while I would bruise myself & im wondering if she’s seen me do it & learned from that…. I’m just heartbroken it hurts me seeing her hurt herself like this😔❤️

Any ideas on what I can do to help teach her not too?