IS SOMETHING WRONG WITH ME (in tears)

Ok! AF was due the 1st of this month! Im starting to get uncomfortable cramps (in my lower belly & butt) TMI sorry! Sometimes they are unbearable I got some nausea but still getting BFN's i took another test this morning my doctor wont be able to get me in into the 20th. Am i testing wrong or is my cycle changing.! This can't be normal. I posted about this b4 but not its different. I feel funny. Im kinda freaking out.