Please, remember that it is against the AN Terms of Service to give medical advice. Stick with non-medical ideas only.
OP, I strongly encourage you to see your PCP. The suggestion of keeping a journal/diary is a good one. Maybe you'll see a pattern.
My husband I have worked nights for years, and we've had to learn how to take care of ourselves.
It's very easy to become dehydrated. Your eating schedule is also worrisome. You could be waking up because your body is telling you it wants foooood!
One of the hazards of being a nurse, but especially one who works nights is that you become very good at tuning out your own body signals (while rushing around taking care of everyone else's). Hunger and thirst alarms may be turned way down for you or even turned off entirely. Going 20 hours without eating anything more substantial than crackers is, well, crackers.
You may not have a lot of time to eat at work, but you can pack things like string cheese, hard boiled eggs, fruit, granola bars, frozen meals. Eat a few bites of something throughout the shift, and have a bowl of oatmeal or a grilled cheese sandwich or even some leftover supper before going to bed.
When you see your PCP, you can also ask about seasonal allergies. That could be a factor, too.
Try hydrating and eating and making sure your sleep mask isn't too tight. Talk to your PCP. And keep a journal.
Taking meds isn't the worst thing in the world if you need them.
I hope you can find something that works for you.