Is my husband keeping something???

So today one of my Glow plan objectives was to share a secret with my partner. Well we are only married a month tomorrow and my first instinct was one of satisfaction. I said to myself, "that's an easy one!" See, in my head we have no secrets. We have talked to one another about life from beginning to end. Or so I thought. I asked him, casually, while laying in his arms if he has any secrets that u didn't know about. He replied "I have lots of things u don't know about...just like u have things I don't know about!" Now, this floored me because I honestly don't!!! After a long conversation, I explained to him that I only asked because it was on my to-do list from Glow he receded and stated that he doesn't have any secrets and he was only saying that   because I asked. I love him and I so WANT to believe him but I'm feeling something is wrong! It's hindering our intimacy now and I'm feeling sad when I'm with him.  Am I over reacting? Please help.