Long breathing after 3-4 mins. On it.

Today I came back to home from corona isolation .i was detected with Asymptomatic corona and was in isolation since 28july and from today onwards I will be in home quarantine during whole stay my blood oxygen level never fall down below 97 and i didnt had any fever,one time I had tiredness only, but from yesterday I need to take long breath after 4-5 mins ( i can able to take normal breath as well as doing pranayam( 10 count)  everyday without any issue . I checked my blood oxygen level after walking 6 minutes its normal (99%) I dont feel any congestion in the chest nor cough . Now taking Pee-hist syrup and vit c tablets nothing else The doctor at corona quarantine center said that its totally fine u will recover from it . Please suggest is it due to my anxiety or else because i m continuously thiking on it .