weird situation? pregnant?

So before I start I've taken about 4 different brand pregnancy tests and all negative.. I have a doctors apt for Thursday but anyways... 
I have an almost 1.5 year old baby. 
I have been feeling what feels like kicks. And my stomach has been hurting when I wake up and sometimes my back hurts(though could be the way I sleep on it) 
I'm asking if I have a negative test result could I still be pregnant? Has anyone experienced this?