I just want you to know it's normal to feel abandoned in such a situation. It may be hard for you to see, but you are actually quite fortunate. Four months is a short maternity leave. Here it is customary that new moms take a full year off. Perhaps consider what you can do in those months to better yourself. Maybe see a fill in therapist, take a course, take a short trip, join a group therapy, take up a new hobby....