My Toddler's Crying Problem

My 2-year-old little girl had been a little difficult to handle lately. She cried easily, day and night. It was disturbing especially during midnight, whereby she just burst into loud cries shouting "papa" or "mama" once she realized that neither of us were sleeping beside her, and it was difficult to calm her down and put her back into sleep without one of us being fully awake. Certainly, this had disturbed our sleep. Our tiredness due to lack of sleep had led to some other problems like lower tolerance level of her wrong actions - when she did something wrong and we punished her she started crying again... The cycle repeated and we could not break it...

I have been wondering if this can be due to the fact that I have recently returned to work after being a homemaker for 1 year plus. At first we did not think it was a big change to her because she has been attending a full day childcare for 9 months and all along she has been doing well. However, after the 3-day long weekend (with a public holiday), I noticed that she has been behaving well and I realized that what she wanted was more attention from the parents! She probably has felt the changes after I started working. Naturally, I feel tired at night after returning from work and have less energy and time to spend with her. Furthermore, I still need to do a little housework, and give some attention to the elder brother who is entering primary school next year, monitoring his progress in school related work. Sometimes I also need a break to watch TV / surf Internet, which doesn't make her feel very happy. Another big change for her is probably that I no longer take her to school every morning. Usually I leave home before she even got up. Although she is very attached to the father, she probably needs me around as well.

My girl had actually been very well behaved since birth, especially compared to the brother, who was a very difficult infant. (Nevertheless he has turned out to be one of the best behaved kids among his friends and makes us really proud of him.) She made little noises when she was hungry, seldom gave problems at night, slept early at night and slept through the nights from an early age. Sometimes when she woke up at 7am, she did not even cry to wake us up; she just stayed quiet by herself unless she was very hungry. As she grew into a toddler, her words always made us laugh, and she knows what to say at the right timing to melt our heart. :) So there must be a reason for her to cry - which I thought could be feeling insecure. Her cries during midnight may be due to nightmares as we punish or spank her during the day. (Well, some older people believe that this phenomena is caused by the disturb of some ghosts/spirits, but I prefer to look at it logically.)

Now the challenge is how I can keep up her good behavior during weekdays. I may need to boost my physical stamina by exercising more and taking supplements, or get someone to help with housework so that I can give her more attention at nights. Although sometimes I feel so sleepy and can't attend to her, I believe that my love to her will give me power to stay stronger... and help her go through this stage of hurdle. Pray for us!