Any tips for breastfeeding?

My baby girl is 8weeks now I try to breastfeeding her in first few weeks and got no sleep so I change her to famula and turn out that she won't break wind for me.she cry when the first second I put her down than I thought maybe I should go with breastfeeding,but she don't have enough and I can feel that she is lighter when she is breastfeeding!she has small green poo sometimes .i am all over the place breastfeeding bottle feeding , it's just so hard ! I am breastfeeding her now and get so confused she cry all the time and I don't know should I top her up with famula or not?