Thoughts?

I have an appointment on 1/9 for my yearly and pap. but I am currently 20 days late. ( I am just holding off till my appointment to see whats going on) I took 2 first responce test on 12/2 and 12/10 and both were negative. I am always regular and never miss unless I was pregnant. What are your thoughts? I dont know if I should try another brand of test and test again or just hold off till my appointment. I know regardless I will be seeing the doctor in few weeks. But just wanted other's options what this could be?