I keep getting a jumping sensation in my stomach , right above my navel. It s really bizarre. Doesn t hurt at all, just feels strange, and is a bit annoying. Have had this for a little over a week. And my lower back aches, around the area of my kidneys and I ve had a lot of frequent urination . And some severe headaches (although maybe this is totally unrelated to the other??). I ve taken two pregnancy tests which were both negative. Any suggestions as to what might be causing this?