It could be your hormones just acting up still without the full blown depression. However, it has been suggested that I still have post partum depression and I have a HUGE temper problem, but I am also extremely depressed. I would personally suggest seing a therapist and asking your regular doctor.
are you getting any help emotionally from your husband, because i never did and almost 4 years have went by and 2 children and things just got worse for me..soo bad that just the other day i finally called and made an appt to see a shrink! i think it will help to talk with someone outside of your family, sort of like your doing now, which is good first step....your aware enough to know that this isn't you and it's not a fun situation...so the next step is to seek professionaly help...it doen'st mean your crazy or even sick if you go get help....it just means your going through a rough time right now...but if you let it go you will go crazy! i did!!! lol!
seriouisly though...make the call, make an appt...it WILL help just to talk and get it out