28 weeks and my SO says his feelings have changed 😥

After 6 years together and me being 28 weeks pregnant I am absolutely devestated to say my SO has announced that his feelings towards me have changed and he doesn't know if he wants us to be together anymore. I have brought up his 8 year old daughter (from a previous relationship) and we have always been so strong! I am confused and don't know weither or not I should just walk away for myself and for our unborn baby. He has slept on the sofa for 5 nights now and I am sick of crying! He means the world to me and I am holding on because I want a family with him more than anything. I just don't know if this is worth it with the way he's making me feel..