Oh, Mona -- so sorry -- I was offline most of yesterday!!
I am pretty sure M would have worked in the sweater. And I suspect the pants would work in your regular GAP size -- that is what I ordered and they have a roomy fit.
I have a "for friends" coupon I can give you. I don't know if it will work on stuff that is on sale, but when we see each other, we can figure that out.
Also, I will bring my S sweater for you to try on. In this style, the S might actually work, also. I will bring both sweaters so you can compare colours as well.