Sleeping

Brooke
Just after some advice or asking others to share there sleep experiences as I'm going crazy at night!
My girl is 7 months and is fine with sleep during the day she goes down into her cot white noise on lights out (night light on) cries for a second when I put her down but by the time I've left the room she is fine and asleep in a few minutes 
Night time is a completely different story! Same exact routine as we do for day naps always put her down awake with white noise etc and she screams for an hour non stop until she will finally give in and sleep.
Does anyone else have this trouble? She is getting enough sleep for her age usually she naps between 2-4 hrs a day depending and at night once she falls asleep it's normally from 8-8 with 1-3 feeds (breastfed) 
I let her CIO as we have tried the gentle methods and it seemed to prolong the crying for 2-3 hrs
Just not sure if it's normal for her and it's just how she is or will she learn? We have had the same routine for two weeks now and no changes yet.