It's been almost two months since my mother tested negative from Corona. But from last two days suddenly her oxygen is dropping to 89-90 when she is lying down or resting, oxygen levels are ok when is not resting or lying but as soon she tries to sleep there is a drop in oxygen level and she wakes up coughing .this has happened last month also but after that it never happen now suddenly again she is facing this issue after one month ,this time she is coughing also.I Don't understand what to do next