I feel so upset, I hurt my baby

Yesterday my baby was 4 months old. MOTN he flipped twice after I changed his diaper while I wasn't looking and landed on the floor. He cried when he fell, his face hit the pail on the floor. Luckily he landed on his hands and his head did not hit the floor. Later he was on tummy time and I guess he was tired and he fell forward, his face hitting on a toy I placed there for him to see. He did not cry, but his face was a little red. Later my mil asks me to cut his nails, but it's a little short and I accidentally cut his flesh and he cried. It bled v long as well. 😭😭😭 I feel like a useless mother. Can't do anything properly... #firsttimemom