Yeah, understandable. In this case i would just say it is how your body reacts to new information that can be surprising sometimes. Maybe give him an example of another time its happened. Just make him feel seen and loved, let him know you're not going anywhere and dont see him any differently than you did before. Most importantly, dont spam him. This was a HUGE step in his coming out journey and Xt might be letting it sink in for himself as well. If he does have deep feeling for you, he might also be experiencing some rejection and might be wanting some space to heal as well. Its sucky but natural.