Chemotherapy and an R AKA

I'm not sure how much progress I'm supposed to be making while doing chemotherapy. I'm 23 F and was diagnosed with stage 3 spidel cell soft tissue sarcoma. My leg was amputated in April of this year. I've been feeling like I should be able to start to walk by now, but I feel so tired and like my heart is beating out of my chest when I use my walker to go to the bathroom. I'm also experiencing a lot of swelling. Sitting all the time isn't helping me with weight fluctuations. Should I do physical therapy or wait until I'm done with chemotherapy? If so, how do I feel more whole in the mean time? My lost independence has really affected me mentally. Should I wear my silicone prosthetic sock too?