Claude Code using 10-15% of my usage when I accidentally click enter and cancel within 2 seconds

I am on the basic pro plan, and have been messing around with Claude Code (Opus). I just had it generate a locally hosted webpage for me, and started to tell it about a bug. I hit enter instead of the ' key before my message was finished, and hit escape immediately. I checked my session usage (which I micromanage right now as I learn what uses up token the most), and it went up 12%. This is now the second time this has happened. Why is this happening? Feels like a complete waste of my usage. It took maybe 20% of my session usage to build the webpage, but now 12% to think for no more than a second.