did you measure the gauge? just take a section of the piece you knitted, place rulers on top (or measuring tapes) and count the stitches and rows that fall within a square of 10 by 10 cm or 4 by 4 inches.
mostly you measure over stochinette stitch - sometimes the pattern calls for something else.
do not measure edge stitches. Take a piece out of the middle of the garment.
your pattern should give some information on what they wanted for that.
if your gauge is right, then the problem is somewhere else. if it is wrong, tell us what came out of your counting and out of the pattern and we help you to fix the pattern for your yarn.
Continental Knitter with passion, pretty busy and always onto something new.
I have been away from the forum for a bit, but I am still around!