Dear MAYLIS, you are having symptoms of viral flu
... In this case You have to rule out if there is any causative allergens for example, dusts, cats, or else..
You can have good anti-allergic drug along with syrup for dry cough
.. Plus You have to inhale steam of plain water for 10-15 min to help open your nose blockage.. And i am very much sure that you will soon fine betterment
Consult GP if condition persists.