Do I have Dementia or something?

Well lately, I have noticed that my mind has seem to wander a bit or when I look at an object that I know what its called, another name pops into my head for some reason. For instance, I looked at a cover(bed) and thought towel(bath) for some reason. Also, I am very forgetful. Sometimes I could think of something and like a few seconds later, BAM!! instant memory blank, and it takes a few mins to remember just what I was thinking about. Also, I tend to misplace stuff a lot and frequently, like my phone and other things. It could just be anxiety. The thought of possibly having these sicknesses makes it even worse. I am 18 years old. I know most people will just answer me and tell me that I am depressed or anxiety or something on those lines. I feel like its something more. I have also been to therapy.