Some good old-fashioned CASTEROIL should run whatever's ailing you right out of your system. Remember casteroil?
But if you're not into any of the old-school remedies, Robitussin is very good (Remeber Chris Rock said that his father used "Tussin" for EVERYTHING
). Nyquil is very, very good. Also Three 6's is another good old-school medicine that works well. This medicine tastes just as bad, if not worse, than Casteroil, but it works.
Just remember to consult your doctor about any illnesses. You may not be dealing with a cold, but something else which is why the medication that you've been taking has not been working.
HOPE YOU FEEL BETTER AND GOD BLESS.