Pregnant and Nursing

Hello. I'm new here.  I have a 15 mo. old preemie DD and just foundo out that I'm 4 weeks pregnant. :o)  This baby is a surprise (as was our DD).  I plan on nursing through the pregnancy, as long as my DD wants to. So, I'm here looking for advice and support.

What do I need to know? What can I expect in the weeks to come? 

I haven't had much breast pain (not like w/ DD) but at times I do feel engorged (but am not actually engorged). Is this normal?

Thank you for the help.  :o)