Really struggling with my emotions

So basically my little girl is 10 days old i already have a 5 year old and I'm really struggling to keep my emotions together. I just want to cry all the time for no reason.. I have to lock myself in the bathroom so I don't do it infront of my husband cause I literally don't have any reason for crying! I feel like I'm just failing at everything just now my little girl wouldn't settle this morning for a good 15 minutes and I just felt so useless. It's horrible. Anyone else going through the same thing?