Speech Issues

Okay so I hope someone out there reads my blog and responds with some good advice. Abbi is way behind in her speech development which I know is normal, but my biggest concern is that she has actually regressed. She has completely stopped saying things she used to be able to say and has even forgotten signs she used to know. She knew all of her colors and now won't tell us any of them. Has anyone else out there had any of these problems with their child??