Is it safe to breastfeed my baby if I am pregnant?

Yes. Moms have done it for centuries. You can safely nurse a toddler through a pregnancy. As long as your health and the unborn baby's heath are fine, it is ok. If you are having problems or your unborn child is not growing, etc. Then you may need to stop. Your OB can assist you as your pregnancy progresses.
Yes. Yes, it's certainly safe. Your supply may start to decrease though, and many women wean during pregnancy, but it is safe to continue nursing if you'd like.