Your job is so, so hard.
I can't imagine the toll it must take on your mentality. Especially on someone so young.

Talk to some people who have been there for a long time about how they cope with these feelings, because I promise you they have had them too.

And remember, this isn't all down to you. There are eight billion of us on this planet now, and each of us has a responsibility to help and support eachother in the best ways that we can.

What you are doing is a heavy load to carry. Acknowledge; accept that you cannot do everything, give yourself the grace that you would give others.