@Kijikun definitely burden her. it's a burden she *wants* to take from you because she cares, AND because it's less of a spoon drain for her than for you, so it's less costly overall in terms of both time and emotional resources. she gets to feel useful, she gets to help make you feel better and safer, it's a pretty powerful feeling, and it will make her grandchild happy. she doesn't get *nothing* from helping you. you can not carry this on your own. trying will only push you farther down, and it will probably hurt her and her bestie to see it happen. let her handle some of the weight until you're back on your feet, and then pay her back, even if just in gratitude and little tasks. it's how caring social relationships are supposed to work. she obviously thinks you're worth it.
@reiyel put that very eloquently and i might nick that explanation sometime, so I'm just gonna agree with everything they said. If you were really being a burden, she wouldnt have offered to help.