Daily stresses.
Teri is a new mother so she has new responsibilities and new stresses added into her daily life/routine which is already busy and stressful. This is very common and very similar for many women, once a baby comes along a lot more work and stress is created and it's about trying to balance everything and deal with these stresses. There is no indication here that Teri is mentally unwell post natally just very stressed out from her new daily life.