It is not easy to balance looking after kids and the home while studying for an exam. Some guidelines can be suggested-
a) Try to do abdominal deep breathing exercises at a fixed time every day.
b) Spending some time on recreational activities such as taking a walk with the children would be a good way of bonding with them and also help you get some fresh oxygen and some exercise.
c) Make a time schedule for yourself to balance study time, house work time and time with family.
d) Do not feel guilty about spending time on yourself. If you are satisfied with your progress in life, you would prove to be a better mother.
e) Stop being a perfectionist. Some days without perfect cooking and cleaning would not hurt anyone.
f) Try to get extended family support to help with the children or with housework.