Possible movements?

So I keep feeling like a thumping right between my hips in the middle, it goes on for sometimes 20 or so minutes then stops. It's very consistent, almost like a steady heartbeat feeling. Is this her kicking or just some kind of other odd sensation? I'm 20x6 today and at 19x1 I know she was extremely low, so it makes sense to me with where she is just wondering if it's normal & her being active or if it might be something else?