Hello there, I just wanted to say that I have an 8 month baby girl and I'm still at my second year of my PhD life,, What I have done is working Saturday and Sunday instead of Tuesday and Thursday and putting my baby 3 days at a nursery,, that would work with you if you have a partner or a friend that can look after your baby on holidays,,, Also in most universities there are usually funds that you can apply to (childcare trust fund) Just ask about them and they will help you in childcare cost to a reasonable level.
Do not worry, life will go on, it was very difficult at the beginning for me to cope with motherhood and study and still is, but always remember you'll have a life time to enjoy with your baby after graduation and also your doing all of this to give them a better future,,,:)