I hear you, Antonia, and thanks for joining in this conversation. I understand everything you've shared about caffeine for yourself. When one is feeling well, caffeine can really affect one's sleep patterns when it's taken so close to bedtime. However, the fatigue associated with any kind of asthma attack can seem to override any stimulant.
I, myself, stopped drinking caffeine so many years ago. I found that I never had issues falling asleep. However, if I had caffeine during the day, I would wake up at 3 am - eyes wide open and raring to go! I attributed it to the caffeine.
Wishing you well,
Leon (site moderator asthma.net)