Nursing 3-4 week old to sleep

Hi, my girl is 3-4 weeks old. Recently, it has been getting more difficult to get her to fall asleep at night. She needs to latch on and suckle herself to sleep. Once she is transferred to the cot, she wakes up and cries/fusses non stop even though she is fed and diaper is not soiled. Is this colic? Would getting a pacifier help? Any solution? Thanks.