phantom smells

has anyone else experienced this? recently i’ve been smelling really strange things that aren’t there like chocolate or lemons or something oddly specific but has no presence in my house. i read it can be caused by a common illness like a cold or allergies but i have no other symptoms of these. the other explanations are big problems like brain tumors or epilepsy or the such. am i just going crazy? i’m not one to assume there’s something wrong with me, i’m a realistic person, but this is just weird. maybe my house is just haunted lol