Killing a creature that is hurt

Hello EA 🙂 

I was out hiking the other day and on the path there was a very big beetle on its back, slowly wiggeling his little feet and clearly couldnt flip over on his legs. I flipped him, and saw that he was really hurt and it looked like someone had stepped on him. I decided to end his life, and I felt soooo bad after. Maybe I interferred with his process, or? I dont know, my intention was good and I said a prayer before I did it, but it left me feeling really bad. Is there anything such as a "mercy kill"? Ouff... Tthe next day I had a similar encounter with a tiny mouse, but this time I left him alone after giving him some love. Dont know what is best. 

Thank you! So glad you exsist!