Sounds to me like she is going to have her period. Our Zuzi usually is taken out for pee and poo four times a day. But when she is on her period she goes outside may be 8 times.
Also, cleaning her area like almost twenty minutes. It is their way to keep themselves clean. When she had her period for first time it was so weird to me but then we discussed with our vet and he said that it is completely normal.
Changing her behavior is also completely normal.Just like a woman
Just kidding of course
It is normal for her to be much more nervous. Also, plays and games are not so exciting for her and she might not be interested.
Basically the only thing they love to do during that time is sleeping and cleaning themslves. You might see her as a completely different dog.
The usual begs for cuddles are also gone which is really amazing, no?