Hello,
with blood sugars at this level you need to be on insulin immediately. Please discuss this with your doctor and tell them that your sugars are so high. It is very important to bring your sugars down. And yes, levels can change dramatically during pregnancy and blood sugars become much harder to control.
first thing is you need to cut out all refined and easy to digest carbs. Particualrly while you aren't on insulin. So for now don't eat bread, rice, pasta, fruits. Eat plenty of veges (except corn and potato), meats, regular fat unsweetened dairy, eggs, nuts etc.
Please also try to walk at least 30 minutes after eating each meal (this will also help to bring your sugars down).
Drink plenty of water. No sweetened drinks or fruit juices.
Please see your doctor again asap. My recommendations will help, but you need the input and assistance and proper medication from your doctor.
Everything changes with diabetes when pregnant. Some times you have to use insulin during pregnancy but can go right back to your pre-pregnancy regimen after you deliver. It is nothing you have done but sometimes more difficult to manage.