Anxiety is so exhausting

I don't sleep much at night because I'm so stressed out, but I can't drink too much caffeine to keep myself awake because it'll make me even more anxious. 2 cups of coffee per day is about as much as I can handle, but that's not enough to keep me alert. I have to be "on" most of the day because I work with kids, but it's so hard. My head always hurts and I zone out all the time because I'm so tired. I wish I could sleep at night but my heart beats like it's running a marathon and it's so hard to rest when you're like that. I wish I could hibernate like a bear for a few months. I'm so tired and I don't know what to do.