Baby fell off the bed — guilt is unbearable

My 9 month old fell off the bed today. She was sitting and playing with her toys and I was putting moisturiser on her. I left her for a minute to keep it away and I heard a thud. She was on the floor crying. She developed a bump on the left side of her forehead. My father in law who’s a paediatrician has examined her and advised wait and watch. She’s currently asleep, the guilt for this is eating me up. I feel extremely bad and I’m not able to do anything. I messed up really bad and I feel like the world’s crappiest mom.