My dog seems to be constipated and is vomiting bile?

She has been trying to go poop all day and she keeps vomiting clear bile. She won't stop. I do not know what is happening but I am very concerned. Right now she is hiding under the desk and wont come out. The bile almost looks like drool and hangs off her face. I try to clean off the bile but she is growling so I don't. Please help me!