Congratulations on your second, healthy baby!
As mother of a two-year-old (the "terrible twos") and a four-week-old, you really have your hands full! No wonder you feel like you're losing your identity. If you're not chasing down the two-year-old, you're busy nursing the newborn!
The glass cell in your dream is a metaphor for being able to "see the world" carrying on around you -- but not being able to participate -- because of your maternal responsibilities. The four cellmates in the dream most likely are a reference to your family. As a family of four, you may be feeling like you all are "stuck" in your current situation together. The current financial difficulties, of course, only heighten your sense of constraint.
Now that you are shouldering the twin responsibilities of family and finances, it's apparent that "the grass has never looked greener" on the other side of your commitments. (Nor the sky bluer!) Your trip in the elevator for food may even be a reference to getting "up and down" (in the middle of the night) to feed your newborn! (Will it ever end?)
It's a challenging time, Beth, but we hope that, when you feel trapped, you will draw upon your experience as a mother to know that these things, too, shall pass. One day (sooner than you think!) your children will be all grown up! Then you will look back upon this period, and recognize your dedication to your children as one of your life's crowning achievements!