Depression during pregnancy

Have any of you other mamas experienced depression during pregnancy? I suffered from it years ago, but after years of nothing it's back at 24 weeks. I feel like it could be hormonal, lack of sleep, or just par for the course, but it's hard to tell because I have a history. Any mamas experiencing it for the first time due to hormones? I'm trying not to get myself worked up about it, but feel like maybe I should get my hormones looked at to make sure they're within normal range.