Hello I have a 4 year old staffy and she has suddenly started crying all the time and trying to dig on the sofa, she recently got left alone with a dog by accident is she pregnant or is it something else? Hate seeing my baby like this!

If she was in season at the time, OF COURSE SHE'S PROBABLY PREGNANT!!   Conception in the bitch is far more likely than with humans, because they won't accept a male to mate with, unless she's right on to conceive.

How 'recently' did this happen because frankly if she is pregnant and anywhere near 62 days from when it happened, she may be about to whelp.  

You need A VET, to confirm a pregnancy and to help you with the whelping since you clearly don't know what you are doing.   And if she is 'crying all the time' that alone would have me off to my vet!

A pregnancy should have been pretty obvious - INCREASED GIRTH!

Definitely vet today .as mamabas says if she is pregnant u and her need help .if she isn't something isn't right and needs professional hands in attention

Any updates?

I wouldn't find it surprising for the OP not to come back after the initial response.

It could also be a false pregnancy, of course....