Mommy's working full time!

How many mommy's are still working full time? I am currently. I work 6 days a week for the postal service. I usually get 2 afternoons off a week and I live for those days! I can choose to cut my hours at any time. Im almost 35 weeks and seriously considering telling my boss no more afternoons. We have 3 full time boys and 2 part time every other weekend. The house work and working are getting to be too much and I have no energy once I get home, but I can't get passed lowering my income. I'm a control freak and I constantly worry about money (even if there's no need which is usually how it is) should I just suck it up and not worry?