Postpartum depression!

So my youngest is almost 2 (July 30th) and I had really bad PPD after her and I thought it got better but lately my anxiety has been so bad I wake up in the middle of the night crying and running to check in my girls or if they are not home and it happens I make my SO go check the car to “make sure” I didn’t leave them in the car even tho i know where they are. I’m not sure why this is just all the sudden happening again but it’s kid of scary. Can it be the PPD coming back or is this something new?