The dog suddenly doesn't sleep at night and behaves abnormally with grunting. This may be caused by a variety of reasons. Some possible factors include:

It may be feeling unwell, such as pain, digestive problems, or illness. Changes in the surrounding environment, such as noise, new furniture arrangements, etc., may make it feel uneasy. The dog may be feeling lonely or craving attention and wanting interaction with its owner. It could also be that it was frightened or something made it nervous. If you are in estrus, changes in hormone levels may cause abnormal behavior. It is also possible that sleeping habits are disrupted, such as sleeping too much during the day. Eating problems, such as hunger or thirst, may also affect his sleep.