In Scandinavia, we have expressions like "se spøkelser på høylys dag" ("see ghosts in broad daylight"), or "male Fanden på veggen" ("paint the Devil on the wall").
These mean that you always interprete a situation in the worst possible way, or that you always attribute to malice that which otherwise could have been explained by stupidity. It's an intense form of pessismism that can be through paranoia, or by self-victimization, or for any other reason. Whatever happens, it surely means the absolute worst. Whatever someone says, they surely have the worst intentions. The dictionaries define them as "seeing a situation as more negative than it really is", or "being afraid or nervous without any actual reason".
I believe I have heard a similar English idiom, but I cannot for the life of me recall what it was. Can you help me?