Yes bojangles I think its worth the effort for a small amount of money because:
These childcare costs are temporary, they will improve once your children start school, so money maybe short for a while, but it will eventually improve and in the meantime you are hopefully furthering your career, gaining experience etc etc.
You don't say whether or not you are married. If your not married, only living together, then it's even more important for you to stick to your career as if your relationship were to break down, you wouldn't be entitled to the benefits a married woman would get.
Even if you are married, it's still worth maintaining a career in the event of divorce etc.
Your working life spans 45 years, childcare costs will gradually get smaller and smaller and will be zero once in secondary school.
I had twins and decided not to go back to work because of the reasons you cited - I decision I regret now even though I have been happily married for 15 years. I have no career prospects and am having to retrain now at the age of 42. Not moaning, just saying.
I'd say go for it. Grit your teeth and get your chequebook out, its not forever.
Good luck