the father of my child is trying to get full custody from me. how hard would it be for him To get custody from me?

Cps is currently in my life and i have to take random drug tests and alanon classes to get return custody of my children , because i once idmited ive smoked pot. now they think i have a drug problem. all tests came back negative and ive been doing everything i am supposed to be doing and some. at the moment the babies father has temp custody. what are the chances of him getting full custody of my daughter?