Just got the news that I’m in the pre diabetic range

This is really bad, I’m 18 yrs old (female) and my blood work came back as an A1C level of 6.1

My doctor told me that I can still bring it back down and recommended exercise and a high protein diet. Any tips on the diet? I’m going to college really soon and won’t be able to meal prep. My school’s dining hall is buffet style, so I’d really like some advice from other people on what to eat.