New and undiagnosed

Just spent 10 days in hospital. Never had a lung problem but did have GERD briefly. Suddenly couldn't breathe. No air! Blacked out. In hospital received 100% oxygen. Slowly weaned and sent home. Got a "maybe" diagnosis of Interstitial lung disease. Im on no oxygen. Drs said I didnt need it. At rest 02 is 93%. Getting up out of bed and 02 dips 88, 85 %. Drs seem unconcerned. I'm scared! Am I chained to my bed for life? Are my 02 sats ok to go that low as long as they come up?