What is this weird feeling?

I am in a relationship, in which I am very happy in. My boyfriend and I are going to be moving in a place that we can personally call home. But with that thought, I have been having this really weird feeling. It’s nothing bad. But I keep getting a feeling, that even though we are going to be living together, that something is missing. I know it’s not love, but I can’t quite put my finger on it.

I don’t know if this feeling is just a weird hormonal thing, because I am the only one of my friends who doesn’t have a baby, or expecting. But it is possible that that’s what it is.
However we do plan on getting married, and having children someday, just not now.
What do you think this feeling is?