I am nine weeks late! Negative HPTs! :/

I have been sexually active, using the pull out method. I have no symptoms of being pregnant and I am worried. What is going on?

I have been having regular cycles up until December when I was two weeks late...after that it was four weeks...now its seven. Why am I having such irregular periods? I am not stressed out or anything. My body weight is fine.

I am so confused! :/

im about seven weeks late, and have done the same method went to doctor and was negative.