I think my puppy might have swallowed a bone..?

Sunday night I let my shar pei puppy outside and when I let her back in she had a rib bone in her mouth and I obviously took it from her but I think she might of swallowed one because ever since then she's been making gagging noises like she's going to throw up but all she seems to throw up is a yellow foamy liquid. I feel so bad for her. If anyone has any idea to what could be going on with her I'd greatly appreciate it.