Is caffeine basically legal 'drug'?

One can get addicted to it easily, to the point that it physically hurts to not consume it. Overdose can be lethal.

I started with coffee in 10th grade and later began consuming caffeine mints and pills in 12th grade to be able to study with complete awareness even after a long day at school. I stopped but I felt like shit for a while. Then after few weeks I wanted to try it again so I ate 2 tablespoons of coffee powder and my chest area (possibly due to heart) felt weird and my head throbbed badly. Never touched any caffeine source after that.

Is caffeine basically legal 'drug'?
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