She's a brick house

Aidan is losing interest in nursing and that is making me sad. He gets bottles of formula during the day while I am working, and I try to nurse him before I leave for work, when I get home, and before he goes to bed. Recently, though, he will only nurse for a few minutes and then cry. I'm afraid he is weaning early becuase he likes the bottles better!! I don't know what to do.