Weight gain during pregnancy

Ok guys so I’m kinda worried about my weight right now and I know some of the weight is baby but I’m afraid that I’m gaining weight me and yes baby is gaining weight too but basically what I’m asking is how do I sorta loose weight during pregnancy? Bc I don’t want have a 9lb baby and them have to cut me or I tear down there bc this is my first pregnancy so how do I loose weight during pregnancy so I won’t have a big baby or have extra pounds to loose after I give birth ! Wanting to have a 7 or 8 lb baby !!!!