If you're knitting every row, you're working garter stitch.
A knit stitch creates a flat V as it faces you, and a purl bump on the back side. The 'stretched out' sections that you're seeing are the knit stitches.
Garter stitch results in a knit row and a purl row as it faces you, so there will be ridges, rather than every row being the same.
If you knit one row and purl one row, you get stockinette, where all the flat V's are one side and all the purl bumps are on the other.
So it sounds like you're doing it correctly and getting garter stitch. If you want it to be tighter, a thinner needle will give you that.