Is my Sisters EnglishMastiff pregnant and going into Labor?

My sister has an English mastiff. She's been thinking for a while now that she got pregnant. Her dog dakota kept trying to get out of the fence today, when my sister friend pulled up dakota just laid in the yard instead of getting up and barking like usual. When my sister tried putting her in the crate, Dakota refused. Almost an hour later my sister found her in the bath tub (which she hates bath). I am thinking nesting if she is pregnant. I had her bring Dakota over to my house so I could take a look at her. She isnt popped out, but she is pudgy. (could this be because mastiffs carry high and it may be a smaller litter) I took Dakota's temp. and it was 101.0 (do all dogs temp. drop when they are getting ready to go in labor?) Also She had a clearish white discharge (no blood) and her back 4 look swollen and droppy. I tried to see if I could feel any movement from the pups but couldnt tell... What do you think? Do you think she is pregnant and getting ready to go into labor?