Chihuahua X jack Russell?

So my dog is 6 days off her due dat but already showing major signs like nesting her temp is 37.1degress c which has dramatically dropped from 40 dc

She is scratching about in her box and also very VERY clinging towards me she's laid half on me half in the box now her tummy is tight she doesn't want to eat or drink won't go to the loo what does this mean?

By the way I'm 15 and my mum is out at the hospital so no hate