Does my boyfriend regret our baby..😞

Me and my boyfriend are both 18 and we just had our first baby. He's the most perfect little boy. I'm bursting with love! But now I'm starting to think my boyfriend isn't happy about our baby. His sister came over to see our son and when she did she asked how do we feel as new parents. I said exhausted but happy. My boyfriend didn't say anything. She asked him how he felt about being a new parent and he starts crying! She asked if he'snh okay and starts rubbing his back and he just says "Yeah". I left the room so he could be alone with his sister while he cried. We didn't talk about it after she left. Does this mean he regrets our baby and doesn't love him😞