I experienced something similar (minus the hospital visit.) I'd regularly gone with 4-6 cups a day for years, with no noticeable problems. I ran into a particul

I experienced something similar (minus the hospital visit.) I'd regularly gone with 4-6 cups a day for years, with no noticeable problems. I ran into a particularly stressful month, then experienced a 2-month bout with insomnia and anxiety. Insomnia is brutal, and I did everything I could to get over it including eliminating caffeine/coffee completely for around 6-7 months. I didn't experience any issues stopping. After the sleeping and anxiety were under control I figured I'd stick with it - I'd heard others say they experienced a few positive benefits by cutting caffeine completely. I didn't notice anything. When I decided to grab a cup again the productivity boost was pretty amazing. I settled on 1/2 caff up to 11am, then decaf only. I drink a lot less coffee now, and if there's even a hint of an issue sleeping I'll skip it for a day or two.