Toddler fell off the bed

My 27 month old LO fell off our bed while he was sleeping. I went out to the toilet and it hasn’t even been 1min, the next thing I hear is him falling. My bed is a storage bed so it’s quite high about below my pelvis level (I’m 155cm). I don’t know how exactly he fell or which part of him hit the floor first but mainly I am concerned about him hitting his head. Cause by the time I ran to him, he was already sitting up. Cried for less than a min, picked him up and hugged him. Asked him where does it hurt and he touched his head. Then he went back to sleep. Woke him up to see if he could walk and luckily he was walking fine. I felt so bad for leaving him for that short period of time. I really did not expect this to happen and it’s haunting me. It hurts to see him fall. I feel so guilty I could die. I checked his head for any bumps but couldn’t feel any. I will try and check again in the morning once he is awake. Will definitely monitor him for the next 24 hours. I just don’t want anything bad to happen to him, else I’m gonna regret it for the rest of my life. I am getting paranoid. I don’t want him to get any internal injury or in pain 😭💔