As you knit every row (garter stitch), when you finish a row and turn to work the next row the stitches will always appear or present themselves to be worked as purl stitches (the little bump you saw right under the loop on the needle). That is because when you knit you make a vee on one side and a bump on the other. If you look at your work right after you knit a row, but before you turn it you will discover that there is indeed a little vee right below the loop on the needle. But look carefully because the little bumps from the last row are close at hand and they are what you notice first. But if you tug down on the stitches a bit you will see the vees right under the needle.
When you purl you are also making a vee on one side and a bump on the other. In fact you get the exact same stitch if you purl every row as you do if you knit every row. It will still make garter stitch that looks the same on both sides and has the ridges of bumps. But if you purl every row the stitches as you are ready to work them will always present themselves as knits, so it will always have the smooth vee right under the needle. But if you looked at what you had worked before you turn it, there would be purl bumps right under the needle in your right hand.
Knitting is very mysterious. :lol: But once you get it figured out a bit, not quite as mysterious. In a sense there is really only one stitch in knitting and the "knit" and "purl" are two sides of that stitch like the two sides of a coin.
You're doing fine.