I've been in the hospital for Covid back in Aug 2020 due to breathing issues. My oxygen levels are now at 93 with a normal pulse rate, but if I climb stairs or do any kind of activity, my oxygen level drops to 79 and my pulse rate shoots up from 128 to 135. I'm regularly doing breathing exercises and using a spirometer, drinking lots of fluids, and sleeping in a prone position. I'm currently on Nintena 100, Doxolin 400, Mucinac 600, Rantac 150, Azithral 250, and Ecospain 75. Can you suggest how I can increase my oxygen levels?

whatever you are doing , its more than sufficient to increase the saturation