Hello girls! I'm 14 weeks pregnant, and my blood sugar on tests is ele…

Hello girls! I'm 14 weeks pregnant, and my blood sugar on tests is elevated at 5.9 (interestingly, I don't eat sugar at all, nor baked goods). For pregnant women the norm is up to 4, they told me to go on a diet and retake the test in 10 days; if it's the same they want to put me on insulin. Has anyone had this problem? Please share advice ?