Is it normal if coffee doesn't do anything to me?

When I drink coffee, I feel good and ready to go. That's what it's supposed to be. But when I don't drink it, I feel sleepy for the rest of the day. Again, thats what usually happens when you stop for a while or even withdrawal. But if I drink more and more in a day, you would think it just gets ten times more of what one cup does but I'm actually at the same level. I don't feel any more anxious or alert so yeah it could be dangerous cause especially good coffee, I can drink it like nothing almost like water because it's not impacting me in any way. I remember a while ago, I drank some like at 6pm so I didn't get any sleep that night but it's not like I was full of energy and anxious, I was just up. I could've had more and still felt "just awake." So is it normal that drinking coffee doesn't do anything to me?