Feeling guilty

Hi everyone! So I’m feeling pretty guilty and just need some advice or words of encouragement. I really want another baby and so does my fiance. My son is 4, he’s our only child. He was diagnosed with leukemia in July 2023, he’s in remission now but still has to see the oncologist once a month and get chemo every 3 months. I’m just feeing so guilty that I even want another baby. I feel like I should be giving my son all my love and attention even though he’s okay now. The thought of growing our family makes me so happy but I don’t want my son to feel upset when he won’t be able to have my undivided attention all the time. Maybe I’m just overthinking things idk 😭