It's totally normal, and I remember my first year (this is my third) feeling totally overwhelmed and also freaked out that it was all on me to make these parents produce required documentation. I learned that as long as I am requesting and documenting the requests, there is only so much I can do. I also spoke with our principal to clarify if students really WOULD be excluded/sent home and she said "I would really prefer not to", so I relaxed. My third year in, I am still chasing folks down, but I am NOT staying late to do so, and I am not up at night worrying about it.
The one issue that does still stress me out are the families who indicate life-threatening allergies but then do not bring an epi-pen, or bring one with no paperwork. Our school is nut-free and fish/shellfish free, but we have a few kids with random allergies (coconut, pineapple, sesame, sunflower) so there is always a risk. I do have emergency epi-pens and a standing order to use them, but those are for undiagnosed anaphylaxis...
Anyway, hang in there and feel free to vent away- we all get it and have been there too many times to count
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