SPO2 fluctuations

At the beginning of this year I suffered from Influenza, pneumonia which led to ARDS. After 3 months of hospitalization and recovery at rehab, I got an oximeter and a fitbit at home, both show SPO2 fluctuating between 85% to 95% at least twice in a day. This happens even if am not going out for long walks, though haven't noticed this while walking. Lung specialist has given me a timeline of 1 year for full recovery. Are these SPO2 fluctuations normal for someone recovering from ARDS?
Please note, I don't feel any dizziness or anything else during these fluctuations.