I personally would wait a few days then test again. If it's still negative but you haven't started your period, I would go to the doctor.
I had breast tenderness when I was pregnant, so that could very well be a sign for you. You might be pregnant but your hcg levels aren't high enough yet to get a positive. Remember, there's no such thing as a false positive.
My cycles are normal. I my tenderness in my boobs. And I have been nauseous at night time that's about it
Being me I would test everyday. 5 days late would turn a hpt positive at this point. But you could have ovulated late which would make your period start later. Do you have regular cycles? Have you been experiencing any symptoms of pregnancy?