As a sober alcoholic (25 years), I can tell you from my experience that the number of people who say "I think I may be addicted" without actually having a problem is statistically insignificant. Not that you necessarily have an addiction as such, but that you probably sense that you're using (whatever) in a different way than you once did. In other words, you're self-medicating -- and you want to address what it is that you're medicating. Again, that may be acute stress, and a quick fix may do the trick. ("Mental illness" includes things like acute stress, depression, anxiety and so forth, so even if you aren't heading for major psychosis, the feeling that you're going crazy is more than just a feeling. And it's a positive feedback loop -- anxiety about your anxiety is crazy-making.) If you've stepped over the line into real dependency, then it'll take a little more work, and there are a lot of solutions out there. The alternative to getting help is exemplified in the gutters and alleyways of any major city.
On the other hand, medicating aside, you are also describing what I went through during the early onset phase of Lewy Body Dementia about five or six years ago. Not fixable, not fun, a bugger to diagnose, but its progress can be slowed. I ignored the symptoms for long enough (there was always a reasonable explanation) that I now walk around like a late-stage Parkinson's sufferer, get lost on familiar streets, forget the names of the people closest to me, and soil my trousers from time to time despite receiving the best possible medical care.
Are you taking this seriously yet?