Have you seen the sticky? There's lots of people's experiences of nursing through pregnancy there. I'd recommend reading Adventures in Tandem Nursing. Even if you don't intend to tandem, there's lots of information about nursing in pregnancy.
Everyone's experience is different. Personally, I really struggled, but I'm so glad we made it through. My biggest tip is to keep well hydrated. It's amazing the difference it can make.
Congratulations and good luck!