Deja vu is an interesting phenomenon. What your Internet sources did not mention is that it happens to normal people sometimes. Just because you had a feeling of deja vu doesn't mean you have epilepsy, schizophrenia, etc.
The obsessing over it could just be your OCD. I've got OCD too and I obsess over issues as well as little compulsive things I do. I think it is possible to obsess over something so much that you think it applies to you. How could you not, if you think about it all the time, almost? But I honestly don't think those diseases apply to you. Many people occasionally get deja vu.