Falling out of love ?

Lately I've been on a rollercoaster of emotions .. I am happy, then I get sad.. And can cry at the drop of a hat.. Which leads me to believe that my hormones are just way out of wack. 
But lately I've just Been feeling like I'm scared that I don't love my boyfriend as much as he loves me .. We haven't had Sex in a couple weeks really, and for us that's a lonnnnng time . I do love him, he's my man. And I'd do anything for him. But my feelings are just indifferent right now . And I have no idea why. Nothing bad has happened. And when I think of marriage I can't see myself with anyone but him. But I recently took a trip alone to visit family. I wanted to miss him. I wanted to feel that feeling of " I can't wait to get back to see him " and ... It's just not there . I don't know what's wrong with me .. Or what is going on. 
Has anyone else gotten like this.. Is it just a weird phase ? I really hope so. I don't want to feel confused anymore . And I don't know what to think of anything anymore really .