never he can call u mom when he want to and mommy when he wants to its totaly normal no worries
My little guy is five and does not want a kiss good bye in publis--he stated 'Mom someone might see"---Well at home total opposite I can get hugs and kisses all the time...just family. It is just them growing up to understand their surrondings..
Not only is it normal, it's to be expected! It's all part of growing up. It doesn't mean he doesn't need you anymore. He's just exploring his independence. I think it's great that he still likes a goodnight kiss! That should tell you something. He's showing he loves you and is affectionate at home. The reason he doesn't want a kiss goodbye at school is because his friends might see and they would tease him then. It's all perfectly normal, don't worry!
Kids go through different stages but they will always need their mom and dad. Just always be there for him. Don't take it personally when he doesn't want a kiss or hug at that moment. He still needs you and loves you. Hope this helps!