(Concern) If I only drink coffee and carbonated drinks, my stomach immediately feels burning.

Last summer, I drank coffee and carbonated drinks frequently, but as a result, I started experiencing stomach discomfort around fall, so I stopped drinking coffee and carbonated drinks for a while.

But I am the type that must consume caffeine, so I sometimes feel sleepy if I don't drink caffeinated beverages. I want to work feeling energetic after consuming caffeine, but as you all know, coffee and energy drinks are the main sources of caffeine, right?

Are there any other high-caffeine drinks you would recommend? ㅜ