Having trouble with gauge

I am attempting to start a sweater with a gauge of 17 stitches per 4 inches using size 8 needles per the pattern. My local yarn shop did not have the yarn stated in the pattern, but suggested a substitute yarn that I ended up purchasing. I have stitched up 3 gauge swatches using size 8, 9 and now 10 needles, but I keep getting 19 stitches per 4 inches. Am I crazy? How can this keep happening? Do I need different yarn or different hands? Thanks for any insight.

Different yarn. The stuff they sold you is probably too thin to get that gauge with. What yarn is it?

The yarn I bought is “KIM extra light yarn” and the yard from the pattern is Knit One Crochet Too 2nd Time Cotton. Both are cotton/acrylic and the KIM gauge says 19 stitches/4in with “7-8” needles. I just can’t believe I’m still getting 19 stitches with size 10 needles. I’m afraid my stitches will start to look too loose if I keep moving up in needles.

I think it’s too thin a yarn to get the pattern gauge. Though this site calls it a worsted and the gauge is 5 st/inch or 7-8, which explains the 19sts/4" gauge. The Knit One yarn seems to be a bit thicker.