Ask yourself, if this was a Human, what would I do? After that, act accordingly.
Hello & welcome....It sounds as if you have a serious issue on your hands....This forum is NOT for emergencies....You don't state the age or breed of your dog, so it's impossible for us to even quess what might be wrong.....
Please, do not wait any longer....Two days is long enough! Get her to her Vet ASAP.....She needs help, now! Let us know what you find out & Good luck....I hope her illness can be resolved.........Karla
I would take her immediately to the vet. This may be nothing more than an infection which has knocked her energy for six....or it may be something serious. You don't know, and the safest thing is get her some medical help.
If it's any consolation, a year or two back my dog had acute diarrhea and vomiting for a day or two. Tests for this and that were normal, so the vet decided she had picked up a "tummy bug". She was fine after 24 hours. She also went off her legs somewhat. That did worry me, but the vet reckoned the whole incident had exhausted her, as she is no youngster. There were no more signs of leg weakness after she recovered.
However, that may not be the case for your dog, and this may be something else. I would take her to the vet immediately. Take a stool sample, and a urine sample with you if you can. It will save time if tests need to be run.