I've been on Ritalin for about three years now. I've noticed that if I forget to take it, I get really, really anxious, almost paranoid and I also feel exhausted. And for the past maybe three months, I've noticed that later on in the day, I start feeling like I haven't taken it at all. I have never, ever, ever taken Ritalin to stay up all night or crushed it and snorted it or anything. Is this withdrawal? Can I be dependent on Ritalin even if I always took it as directed?