I looked on the safe fetus website where they list medications and the ingrediants are ok, the pain reliever in it paracetamol is fine and safe in pregnancy and the decongestant wont harm the baby if it isnt used all the time!
Even if it wasnt safe theres a very tiny chance it will harm the baby anyway as u only used it once
Yes Dayquil and Nyqui are not good to take if you are pregnant but like tallgirl said if won't hurt just this one time. My doc recommended Sudafed and that worked great for me. Good luck and hope you feel better