Feeling sad

I feel kind of pathetic saying this, but it is making me sad. I live with my in laws so my 7 month old sees my MIL on a daily basis. However, I do everything for me baby feed him, change diapers, breastfeed. My baby has always preferred me. No one else. He doesn't really like my husband. But he loooves me. He's attached to me. However the past two days my baby completely changed and every time he sees my MIL he throws himself on her or even once cried when I took him from her. Why did he change all of a sudden? I'm so confused. My MIL is having a thrill with this already telling everyone how he likes her more than his mom 😔😒😒