Problem at night with our female staffie

Hi,
Recently we have been having problems with our female (spayed) staffie Sascha. At night she becomes very restless and clingy. She also pants a lot. Its not hot in our lounge but she is showing the signs of having hot flushes. She is fine during the day and has a healthy appetite. as soon as we go to bed she seems to calm down(we live in a small bungalow so would hear her if it continued. Apart from this, she is a very healthy dog.
Any ideas?

How old is Sascha, how long have you had her for. I take it she sleeps in the lounge? Has something changed? If she sleeps in the lounge, is there water on hand? Sorry for all the questions, but it does help to get there.

Sascha is nearly 7 and yes she sleeps in the lounge with clean water. There have been no changes in her life, she has been fine up until recently and gets on well with our other staffie (a boy)