Head injury, fell from shower, hit head on toilet. Two days ago. Pressure sensation inside head. Nausea, no vomit. Can't focus. Should I worry?

Post traumatic syndr. It is always wise to make sure there is nothing serious. See you doctor ASAP for CT immediately. If this is normal, then these symptoms are quite common with head trauma. I usually treat this with homeopathy with excellent success.
Post-concussive synd. If you are having persistent symptoms following a head trauma you should probably seek medical evaluation. These may be post-concussive symptoms.