How do you handle too many tasks on your list?

So, I’m back. Some of you may remember me as the girl that kept freaking out about my new job 4 months ago when I kept making mistakes.

I have been doing a lot better and I’ve been feeling a lot more comfortable now. I can get work done pretty fast and easy with little revision. I have recently passed my 90 day review and there was a lot of positive feedback.

But ever since my two student assistants graduated I’ve been taking on so much more on my plate with no help. Little things need to get done like creating folders, scanning, filing, etc.
We hired a new student assistant to help me out but things are not going that great but it could be too early to tell. He constantly forgets things, makes mistakes, I mean he asks me the simplest questions like “How do I fold this letter in an envelope?” And I constantly tell him to do something three times and offer suggestions. I have to re-do his work and it takes me a couple hours.

It’s only been 3 weeks so I hope it gets better. I made mistakes first starting but I have to show him things like 4 times. I tell him to take notes and he does for a second and stops and thinks he can memorize it.

Anyways, it’s affecting me at work when it gets super busy. I noticed I’ve been making errors in my work since I’ve been training him. Luckiky I catch it before anything happens and now I know how to make corrections without anyone fixing it but I feel incredibly stupid and mad at myself. I am making a bit of mistakes again due to multi-tasking trying to gets things done by a deadline, handling constant interruptions, training him, and fixing his mistakes.

It could be avoided if I just slow down and focus…double check. I like that ts challenging and productive but how do you handle it when there’s a lot to get done and you have to train someone? It makes me stressed out that I made a dumb mistake even though I fixed it. But it makes me doubt myself what else could I have done wrong that I don’t know?

I’m hoping maybe with time he will get better as he is a young college student so I’m giving him the benefit of the doubt. But even simple tasks raises a flag for me. I tell him to file, I check on him 30 minutes later and he doesn’t know where the “personnel” cabinets are… I point at he one right in front of him perfectly labeled…...
I have to keep reminding him each morning to check the mail and messages as he is supposed to. I don’t get it.

I know to slow down and focus, double check, but it’s hard when I have to deal with this. Any tips? I know I shouldn’t be thinking about work but I can’t help it.