please know that this will pass. having a baby is a huge life change. your probly exhausted mentally, which sometimes we tend to overlook in ourselves. dont be so hard on yourself! a qwik tip for you..make a realistic list of 3 things u want to accomplish each day. it always helps me to write things down. when the baby naps, do little things for yourself. start a journal, read a good book, research things online like ...how to's in any thing that interests you...that always motivates me! good luck and be Good to Yourself!
you shouldn't feel sad and helpless you got blessed with a beautiful baby! but sometimes it can get overwhelming! try having someone watch your baby and go out with friends. Its also helpful to be surrounded by a good support system. Or what else will help is try doing something your passionate about like drawing, singing, ect.