Hi,
Your symptoms can be due to sinusitis. Sinusitis can cause dull pressure headaches, sense of fullness in the head and runny nose.
I would suggest you to take steam inhalation 3-4 times a day and once before bedtime. The steam will loosen up the secretions locked inside the sinus so that they flow out easily thereby relieving congestion.
In the meantime schedule an appointment with your GP as if the infection is bad you may need a course of antibiotics.
I would try to get an appointment with your GP. They should be able to tell you more. It could be a sinus infection that you took the wrong type of decongestant for and you are drying up your sinuses instead of moving everything out. This happened to me once. Do you have a fever? What about any other symptoms? The foggyness and all of your other symptoms can be explained from various types of migraines. Excedrin Migraine, heat/cold packs can really help depending upon the type of headache. I would go get checked out though.
Good luck!
Tanja