Leaving baby with friend for first time

Okay I’m being a total helicopter parent I think. My best friend who has experience babysitting lots of babies is going to watch my almost 5 month old for a couple of hours so I can go to the dentist. She’s very very sweet but a little airy sometimes, very forgetful, but loves babies, especially my baby. I’m nervous though. She came over the other day and every little thing I freaked out about. She tried to tickle him but I think tickling is painful especially for little ones so I told her not to (very nicely). She was laying him on her legs and his head was at a slight downward angle and it had been a few min so I told her “hey I think he’s angling downward and it’s not good for the blood flow to be towards his head” and she immediately realized and fixed it. She always talks to him in a very baby voice. I’m just nervous I’ll be gone and he’ll freak out crying and what if she does too much tummy time with him or missed his sleep cue or what if he doesn’t sleep. Or what if she holds him wrong and accidentally hurts him. And I’m nervous about someone else changing his diaper if he ends up needing a diaper change. Agh I’m stressed. I can’t sleep and I just want to cancel my appointment. Also, I’m not trying to be unappreciative towards her, I love her and she’s super sweet, I’m just a very anxious person and think like the worst thoughts. I never thought I would be like this as a parent.