Is Mucinex DM for coughs ok to take while pregnant?

I know it's best to ask a dr. But every time I call I get the stupid answering machine, or she is out to lunch or away etc. I have been trying for like 3 days and cant take it anymore. I have a horrible cough setting in and its driving me nuts especially at night. I cant take liquid medicine because it makes me throw up, even the smell makes me sick. Always has. I looked all over online but cant seem to find weather or not its ok to take. Nothing else seems to work and I need something until I go to the dr on the 6th of April. Im 18 weeks along