I had been knitting for years the way my mother taught me -- we held our yarn in our left hand so I assumed I was knitting continental.
I didn't know many people who knit other than my mom, gramma and auntie and they all knit like me.
When my son was old enough to join a playgroup, I started meeting other knitters who knitted English style. I watched them knit and noticed that they knit their knit stitch through the front of the loop. I had been knitting all along through the back of the loop. I realized that it was so much easier to knit garter stitch through the front so I adapted my knit stitch to the front of the loop but continued to purl the way I had been taught.
When I attended my first knitting class to learn how to make socks the instructor watched me knit, noted my difficulty in getting my gauge anywhere near what the pattern called for and told me I was purling wrong. I was doing exactly what you were doing -- inserting the needle and wrapping the yarn UNDER and OVER the needle and then pulling through.
She showed me how to purl by wrapping the yarn over and then under the needle and pulling it through and my stitches were more even and I was getting my gauge every time.
This is what I figured out -- when you knit through the front of the loop and then purl the way we were purling you are twisting the purl stitch -- when you knit through the back of the loop like I was doing in combination with purling the way we were purling it is called combination knitting like on Anne Modesitt's site.
Watch this movie:
Or you can check out this:
Combination Purl Stitch
Does this help?