Feeding & producing of milk

Hi mummies- I am working mother and my baby is 3 months 22 days now. I always pump milk for baby and one day I can pump around 500ml. It’s enough for my baby one day drinking. But now My milk production was suddenly dropped I can’t even get 150ml the whole day. Night time also less milk so baby not enough milk and cry more and more . How can I get back my milk producing like before. Due to not enough milk now my baby refuse drinking milk from me. Even my holidays baby wants only milk bottle. Any suggestions to get milk producing more? Is there any mummy face same problem before?