I need help apologizing to my stepmom!!!!!?

Okay well lately my son was born and my stepmom has been there to take care of me and the baby. But she's been so close with the baby that I feel that he will get more attached with her than his own mother. So today she took him over to her house without letting me know. I was furious. So I told her to bring him back over, and she did. But I feel that I might have taken it the wrong way and I want to apologize to her. She has done soo many good things for me while I treated her bad. But I'm not good at apologies. I need help somebody. PLEASE!!!