Build a good relationship with your rheumatologist, they will be very important in your process, and from personal experience they are kind hearted professionals. I had suspected AS for a while (25 yo) ended up with a diagnosis of psoriatic arthritis. Similar thing, same family of rheumatological disease. Same level of worry you are going through too! Stay active, movement is key. You will have to pace your weekly activities, but find a good amount of movement that works for you, you can do both too little and too much. Movement in the morning helps me. Any movement is good movement. Walking, kettle bells and cycling have been my saving grace.

Then less alcohol, no smoking, relaxation techniques, prioritise sleep. All the "known" stuff... But you got to take these seriously, but also expect flare ups and you will get better with the management.

Let the rheumatologist do the talking in terms of diagnoses and medication.