I a ssume in your contract that you have a minimum amount of time you need to give to change the contract. It will be obvious by half way through the pregnancy in that it will be harder to hide so parents will know for 4-5 months that you are pregnant and will start asking what your plans are.

Your parents are taking advantage of you and that is where to start. Most caregivers limit the day to 9-10 hours of care so at minimum they need to be paying for two hours of overtime each day. Chances are once you enforce the 10 hour limit they will find a way to pick up and drop off within the alloted time rather than pay. Pick a date and let parents know that as of whatever the date is that your hours are changing because you are being taken advantage of and then open later so you get more time to get ready in the morning (allows for morning sickness to subside or to eat a better breakfast yourself) and I would even close earlier in the evening or open early but close earlier too. Take the family you don't mind and work only their hours and expect the others to fit into them within reason.

As far as your daughter goes remember that by the time the baby comes along she will be used to sharing so it just means she has to share with one other person too. Sometimes we get so worried about things that we go overboard in trying to prevent something that what we really do is teach the child to be upset if that makes any sense. Assume she will be fine and deal with it after if she isn't rather than spending the next few months worrying about it. Just as we teach the daycare kids that they have to accept the new reality it will be the same for your daughter in that she can be as upset as she wants but the baby isn't going back where it came from so she will just have to accept it and nothing you can do can make it all better. It just has to be.

I get that you are setting your sights on a career change. Is it possible to start the courses in January in the sense of finishing the semester just before the baby is born which would shorten the length of time you are in school after the baby is born. You might find that financially the benefits of claiming the months in school on taxes would be beneficial.

But back to the question of taking the time off. It is polite to give the parents plenty of notice and expect that they may leave early which really isn't a bad thing for that last month of pregnancy to have nothing to worry about but your daughter, fixing up the baby's room and getting a few meals down in the freezer AND sitting and resting as much as possible meaning telling them two months before the baby comes you are not starting daycare back till summer at least - leave the date wide open so you have options means a month for them to find new care and a month for you to rest up.

As to the no breakfast that is more a case of putting your foot down and telling them it has to stop. Let them know at drop off that the kids are hungry and that it is the parents' responsibility to feed them not yours. Tell them how much the fee will be for breakfast and that it is paid upfront so you can shop for food. Otherwise morning snack becomes breakfast and snack every day becomes a dish of dry cereal and a glass of milk and served early. Not the kids fault.

By the way congratulations on the pregnancy.