A chair (office type) that raises and lowers may help get the height adjustment of the chair/table/sewing machine to a comfortable height.
Really good lighting might help you see better and not have to lean over as far.
Working for only a short amount of time with lots of breaks so you don't get overtired.
Get a helper or sewing buddy to help with the cutting, ironing.
As you get stronger, you'll be able to do more. Hope you are feeling better soon.