Sick and feeling guilty

So to start I think I have an immune system that barely functions, I've been terribly sick since the beginning of March and now was just diagnosed with the flu. I work as a PA in pediatrics but I wear a mask and wash my hands, etc. We have a 4 month old and my mom took her to their house for a few days because I was diagnosed with the flu to try and keep her from getting it and so I could rest. This is the 2nd time someone has had to do this for us because of illness and I feel useless and like natural selection is telling me I should die already because I can't stop getting sick. I enjoy the break but the guilt eats at me. I also have severe PPA/PPD and just hope my baby isn't wondering where her mom is or feels abandoned. Thanks for letting me get this off my chest.