Hi Olivia. Getting that diabetes diagnosis can really throw you for a loop! You're among friends here - we've all experiences that sense of being overwhelmed and confused. The good new is that these feelings really will pass over time.
What type of diabetes do you have? Are you taking meds? What advice were you given by your doctor?
Contrary to some advice in an earlier response, you do not need to eschew all fat or even alcohol. You do need to moderate your carbohydrate consumption. Many people find that reducing or eliminating starchy carbs like rice, potatoes, pasta, corn, etc. really helps control blood sugar. You'll find that you can replace those calories with lots of fresh veggies, berries, and (yes) healthful fats like olive oil, avocados, nuts, butter, nut butters....it's a long list. I try to allocate my daily calories this way - 35% carbs, 30-40% fat and 30-40% protein. Things like alcohol can cause short term lowering of blood sugar followed by elevated blood sugar, but once you've found what works in your life, you'll be able to have some wine or a beer or a cocktail.
Make sure you have a glucose meter and lots of strips. In the begining you'll want to test to see what causes your blood sugar to spike (rise high and rapidly). To do this, test before you eat, then one and two hours after taking the first bite. Write down what you ate and the quantity. You'll soon find you have a great database of foods that don't cause big fluctuations and those that do. Then you can start to reduce or eliminate those things that cause you trouble.
Anyway, it looks like I'm writing a book, so I'll stop now.
Good luck. Let us know how you do.
Jen