I felt my baby at 14 weeks, and I'm 30 now and i only weigh 114 lbs
At 17weeks you probably aren't feeling the baby yet. Maybe gas bubbles ... But since you're tiny like I was you are probably feeling your skin stretch a lot and its pretty painful and also your hips move and spread apart. That could also be what you're feeling. If you did feel the baby move it wouldn't be enough to hurt you yet. I know the struggle I was 112 when I got pregnant lol.