Really excited to hear about the upcoming meet.
Perhaps it's a good thing regarding the short notice in the sense you don't have time to overthink things. I'm still a meet rookie, so I don't have alot of advice on how to prepare, except to say that:
A. Practice your commands
B. Do a mock meet prior. Do only the 3 lifts and try to imitate a meet. Ramp up as you would at the meet, but stop once you have lifted your planned opener. Focus on form. Wear your singlet.
C. Up to a week or 2 before the meet, you are not going to get any stronger, so focus on getting plenty of rest, but staying loose.
WRT your squatting today, awesome work as always. Your 395 single was what I did earlier this week!! makes me feel even better.