my 4 week old still won't sleep at night!

I'm going crazy. I never had this issue with my daughter. I've been trying to get him to sleep for over an hour. I breastfeed on demand and even let him use me as a paci because most of the time he won't keep a real paci in his mouth. We swaddle and put him in a swing at night. We have tried noise and music, we have a fan going by his bed, we "shush" him. We also give gas drops but we tried gripe water tonight instead.  Ugh, he is great during the day and goes down relatively easy but night is a whole new story. Anyone else? Any suggestions?! Help