HELP........ Figuring gauge

I’ve got a pattern that calls for size 13 needles with a gauge of 13 st=4" and 18 rows= 4" in st st. I’ve substituted a worsted weight yarn for what was sold as a worsted weight and the guage is nowhere near what they call for. It’s too many stitches. I’ve tried sz. 11 and it’s still too many stitches and sz. 10 is too few. I happen to have sz. 10 1/2 but those are still too many stitches. Any ideas?
Thanks for your help.

If the original pattern called for bulky yarn, then you should try doubling the worsted weight (knitting with two strands instead of one) to get the recommended gauge.

No, it’s not a bulky yarn , so I don’t think doubling would work. The pattern is a lightweight cardigan that originally used a ribbon type yarn. I was told by someone that the ribbon is considered worsted weight so I figured worsted would work. Thanks anyway…

Oh, I see…13 stitches to 4" is generally considered “chunky” (chart here) but I’m admittedly :?? about ribbon yarn.