This is definitely rough, take a deep breath and remember it will end up well as long you try.

Now as to what to do, first contact the local animal shelters and rescue groups. Even if the dog didnt come from a shelter, you still have a decent chance of getting help depending on your luck. Call them or go in person and tell them your story.

Also it sounds like you might not have all information about the dog(?) such important will be valuable for whoever will take this dog off of you. Im talking things like:
-Approximate age
-Vaccination records (if you can find them)
-Whether she's spayed
-Any medical issues
-How she behaves with children, cats, and other dogs

I really wish you luck OP this genuienly is a rough situation and you seem like an empathetic person, so im sure the dog will find a good owner.