Week 6 ni memang banyak stretching and ligament changes happening, so pulling sensations tu quite normal! Tapi since it's on one side ja and intermittent, best to mention it to your doctor next visit to make sure semuanya okay, the pelvic ligaments stretch unevenly sometimes and can cause that pulling feeling, a few of my mum friends had the same thing and the doc said it was nothing to worry about, but better safe than sorry especially at this early stage.