I'm assuming since you're using magic loop that you're knitting a fairly small diameter, so would it be possible to tink back one whole row to see where you might have added an extra stitch? Sometimes undoing what you did (slowly so you don't make another mistake) can help.
If you're not doing a yarn over, the only other thing I can think of is that you may have accidentally picked up a stitch between stitches. I sometimes snag the row below when I set my work down or even when I'm pulling yarn through the stitches. This usually pulls the yarn up and the rows below are not even. Do you see anything unusual like that?
Sorry you're having problems with this. Stick with it. Eventually, you'll be magic looping with your eyes closed!