I feel very sad when my bf goes home

My BF and I see each other onc during the week, and Saturday and Sunday we normally spend together. He normally comes to my place. We go for walks, cook together and do coupley Hingis together. When he goes to his place on Sunday night, I feel very sad and lonely. Is this normal?

Am I becoming dependant on him emotionally? How do I avoid this?

I am usually back to normal the following morning.