Having issues with YO

I’ve been knitting on and off since I was 6 but for the past few years I’ve been knitting more, I’m expanding my knitting into more then k1 p2 ect I’ve done a few things that have called for a k1 yo p2tog and did just fine up until I tried to k1 yo k2tog then I some how end up with almost double of what I started with, for instance earlier today I attempted this, I started with 15 stitches and ended up with 26. I’m not exactly sure what I’m doing wrong, perhaps I’m yarning over the wrong way. Any advice would be welcome, I thank you in advance.

Welcome to the forum!
Try it again and watch each stitch as you make it. It may help to put markers every 3 sts so it’s easier to see where the pattern goes wrong.
For the k1 yo, k2 tog: knit 1,bring the yarn to the front between the needles, then bring the yarn to the back over the right needle and knit 2 together.