These are known as antenatal and/or postpartum depression, antenatal and/or postpartum anxiety, antenatal and/or postpartum OCD, postpartum panic disorder, postpartum post-traumatic stress disorder, and postpartum psychosis.
Being affected with one of the above is unfortunately more common than many people think. The newest research says that 15% (or more) of new moms (1 in 7) have some form of postpartum depression (PPD), and that's just looking at ONE illness in the entire spectrum of perinatal (during pregnancy & postpartum) mood and anxiety disorders listed above.
As a birth doula I like to keep a list of current online and local resources to benefit women and families affected by PMAD. One such WONDERFUL online resource is Postpartum Progress. I recommend this website to anyone looking for more information about any of these illnesses!