You've driven up over the hill, over the hardest part of a breakup and are now in a plateau of apathy. It's a good place to be. Or, you might be in denial and the mourning period will hit you when you least expect it. Everyone copes differently in life, so there is no "normal" in this situation. Only what is best for you.
One of my friends also felt like you when she broke up with her boyfriend, but after some time she started to feel really bad like, I guess, you "normally" do when you break up with someone you used to love, so maybe you are gonna get some other feelings soon?
That happened to me after I basically had it with my last boyfriend. At that point I knew it was time to take control over the situation because my emotions weren't getting in the way anymore and I was able to think logically enough to tell him I was completely done with him and his horrible behavior towards me. Really glad it happened too, because ending it all was pretty pain-free.