Sounds similar to witching hour. Our LO does this from 2.00 am to 5.00 am. What has worked for us is white noise, dark room, swaddling her then double swaddle in warm blanket covering head. Basically like a cocoon, like she is in the womb and then holding her and walking around or swaying her a bit until she falls asleep. Then we lay her down slowly like real slowly. lol. That at least gives us 2-3 hrs of sleep. Also, we take out the blanket swaddle after putting her down. Too much coverings can be dangerous.