Depression?

I've been beyond excited about having my son. I'm 35 weeks but we just got my SO's kids for the summer and they've been very stressful and my SO has been working at all hours of the day and night and I just feel like there's a lot on me at home. I'm so stressed to where I feel no connection with my baby anymore and I dont feel excited anymore. I feel lonely and tired and miserable. Is it possible to start experiencing depression this late into pregnancy?