Want to nest but I get tired so easily

Y'all I know I need to be cleaning and packing up this apartment to move. I get so tired I can clean and then boom it hits me to sit down cause of my back. I can't even walk in Walmart without my back hurting my husband says I have to use the driving cart. I tried it and had to get out of it cause I felt crazy in it. I just hate I have not energy and don't want my hubby to do all this work plus his job. Is there anything I can do to get some energy that will not harm baby boy. SOMEONE HELP ME I don't want to keep not doing anything.