I concur with others that you should sub first. There's no way for us to know if it'll be good for you, because maybe being alone to make every decision could also give your anxiety. We are very limited in terms of what we can do as interventions:no oxygen to administer, no code cart, no senior nurses to ask question of (maybe a manager/director is available by phone, but maybe not).
I'm almost never bored. Maybe there's still some school health offices that do no more than pass out band-aids, but here's a list of emergencies I've had this year: 3 students passed out from panic attacks, 3 students with severe enough seizures to call 911 and administer emergency medication, 5+ incidences with a schizophrenic student who stated the voices were telling her to jump, 1 911 call for a first-time asthma attack, multiple concussions from recess (admin and teachers let them run wild!), 1 911 call for a student who got her tongue stuck in a water bottle (call cancelled after I got it out, but it was swollen and purple! Scary!). This is in addition to routine care of diabetics, routine medications for ADHD and such, students who receive tube feedings, run-of-the-mill seizures and fractures, screenings of vision/hearing, approving medication orders, calling providers to clarify orders, evaluating students from a medical point of view for special education services and writing up reports, and of course documenting every last little thing I do, down to every last ice pack and band-aid. Still sound like a boring job?
Edit: forgot to mention the kid who was allergic to peanuts who ate a peanut. That was also not boring! Darn field trips!!!