First it was my left brakelight, then my (standard) head unit, then my left head light and now my rear number plate light has gone out. The park lights all work fine but when i go to driving lights i only have parks on the left, and normal tail lights till i brake in which i only have centre and right. The head unit face comes back on when i hit it so i'm not sure if it's connected to the other problems but what is the likely cause of all this?

checked the fuses?

check the earts and also check that the alternator is charging right, and that the battery terminals are clean and tight