Scared about altitude sickness in north Sikkim

Hi guys, I am a 36 year old asthmatic,(mild one )controlled without inhalers. so I am really scared about falling sick due to altitude sickness , so anybody could share their experience specifically people with asthma how they fared in terms of the health in north sikkkm territory, especially at zero point and Gurudongmar lake? Also,tips on how to stay safe and healthy?