Ohhh that sounds like it could be your baby's first movements! At 17 weeks macam you're in the right timeframe, especially if it's your first pregnancy, some of us don't feel it clearly until a bit later, tapi some feel flutters early. The thing is, first kicks feel macam... subtle lah, like a light tap or bubble popping inside, not the strong kicks you'll feel later, so it's easy to miss or wonder "is this it?" One of my mum friends said her first movements felt exactly like what you described, a gentle push then berbalik, and she thought "eh, weird sensation, sure or not?" Kalau it happens again and feels the same way, it's probably baby saying hello!