Here’s a scary stat: More than 30 million people in the U.S. have diabetes, according to the Centers for Disease Control and Prevention (CDC)—and 25 percent don’t even know they have it.

But it gets worse: 84 million more Americans have pre-diabetes (a.k.a., almost diabetes, when your blood sugar levels are high, but not high enough for full-blown diabetes)—and 90 percent of those people don’t know they have it either, per the CDC.

Back up—remind me what diabetes is again.

Diabetes isn’t just one disease. There are actually three types of diabetes: type 1, type 2, and gestational diabetes. Most people with diabetes have type 2—it happens when your body doesn’t use insulin well and is unable to keep your blood sugar stable, per the CDC.

Type 1 diabetes is much less common—only about 5 percent of those with diabetes have type 1—and it’s essentially an autoimmune disease where your body stops making insulin at all (and as such, can’t regulate blood sugar).

And gestational diabetes occurs in pregnant women—it usually goes away after you give birth, but it can increase your likelihood of developing type 2 diabetes later on, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

via 10 Diabetes Symptoms In Women – How To Know If You Have Diabetes