I went to berlin, since i got off the plane i feel dizzy and unstable.

May be benign: Although cabin pressure in airplanes is usually stable, on occasion, transient block of eustacian tube, perhaps secondary to sinus issues, can be experienced and this will secondarily affect the inner ear causing a dizzy dysequilibration. Simple symptomatic relief available by using either otc dramamine (dimenhydrinate) or meclizine. Highly likely that this is temporary, and if not better in few days, see a doc.