Sorry about your miscarriages. That's horrible.
To answer your questions, it's not necessarily harder to get pregnant when you have diabetes, but it may be harder if your blood sugar is too high. Also, blood sugar that is too high during pregnancy can affect the baby so it's best to get your blood sugar under control before you start trying for a baby. Your doctor or hospital should be able to advise you about that.
You may have to use insulin during pregnancy. It depends if you need it to keep your blood sugar under control as that's really important. For any diabetic, blood sugar levels during pregnancy have to be more tightly controlled than when not pregnant. The insulin can help do that, so, although it might be scary, it's a good thing.