When did you know you were in love?

My boy and I have been together for over 15 months and for a very large portion of that we were only happy when we were happy and when we weren't we hated each other. I don't know what happened to us, but all the sudden something clicked with us. Now even when we are mad at each other, we're still so ridiculously happy. It doesn't make sense to me at all that even if he makes me mad we are still laughing at and with each other until it goes away. We have said I love you since the first day of being exclusive (we had been together for about 5 months prior) but I feel like im finally understanding what that really means. I'm so happy and I just wanted to share.
I'd love to hear other women's stories about when they realized they were in love!!