One idea to get your head flowing again includes heating up a large amount of water to boiling, then let it cool for a minute, then put your head over it and breathe deeply. The moisture helps decrease mucus secretions.
Fill a bowl with warm water. Add five drops of Eucalyptus essential oil. Place your face over the bowl with a towel covering your head. Breath in the steam vapors.
If you would want to buy some medication, sudafed is pretty good at releasing sinus pressure and letting mucus pass through. Eating some hot food like chicken noodle soup can help clear your head up. Another good thing to use is Vicks vapor rub.
I can't take over the counter medicines for sinus problems so what I usually do is boil water and add eucalyptus and menthol to the water. Lean your face over the bowl and cover your head and bowl with the towel to keep the steam from escaping. Take deep breaths through your nose for at least 5 minutes.