To not understand caffiene drinkers

[Frazzld]

I had a cup of tea yesterday at 10am.
I was still having palpitations at midnight, and was wide awake. Didn't sleep until 1am.
Is it just me who is this crazy sensitive to caffiene? How do so many people chug coffee all day and not have any problems?

I'll never forget the time I had an energy drink at the library once when I was at uni, and had to go home shortly afterwards to lie down!

I can drink tea but I can't have fancy cold remedies with caffeine in them as it gives me palpitations. Found out I do actually have a very minor heart issue which means I can't handle big doses of caffeine.