Can postpartum depression come back?

The docs told me I had a little bit of post partum depression because if something happens to my kids I get really sad and depressed till I know all is well amongst other things, if something goes wrong the same thing happens i cant shake it off. Well I went on vacation with my kids and husband and my PPD broke I felt great. I came home and have been home for about two weeks. My husband got his lawn mower back, mowed a part of our grass in our duplex and the man who has been harassing us who also is paid to mow the grass got mad and weed wacked a patch of rhubarb, babies breath, and violets he saw my 17 month old picking yesterday, and its like a wave of sadness is back, I keep crying and Im just so heartbroken for my daughter. Could this be the PPD coming back?