My 22 Month old isn't sleeping through the night anymore--What happened?

Older babies who are difficult to put to bed or who wake at intervals during the night need a fixed bedtime routine and, sometimes, a period of training in how to fall asleep by themselves and resettle themselves when they wake. If your baby's sleep problem did not cause these reasons like illness, changes in routine,and feeding problems. You can try some of the following ways: Check your baby is not too hot or too cold. Keep the room at about 18C and don't put the cot close to a heater. Don't wrap your baby up tightly. Cover her with one or two light blankets. You can teach her to sleep better at night. A period of nighttime training using controlled crying or gradual withdrawal will stop your baby's sleep problems becoming entrenched. Accept that if you have always comforted your baby promptly when she wakes, you are sure to feel anxious about this process at first. When your baby cries don't rush in; wait for 5 minutes, then enter the room and say "good night" or "back to sleep now"(choose your own phrase). Then leave, even if your baby is still crying. Wait for 10 minutes before you return to your baby and repeat the phrase again in a calm,cheerful tone. Repeat the sequence again after a 15-minute interval, then again after a maximum interval of 20 minutes. Now restart the procedure entering the room at 5-, 10-, 15-, and 20-minute intervals. Don't give up if your baby continues to cry. Parents need to support each other through this process as most babies protest vigorously at first. Use the same technique consistently each night; it should begin to have an effect within 6-10days. Good Luck!