I am 17 yrs old and 1 week 2 days late I have sex regularly. But I am very regular I took a pregnancy est on 5 day of being late and it was negative can someone help me I: need answers.

If you are having sex regularly ( no mention of birth control ?) but even with birth control you can become pregnant.
Depending on date of conception, you may have to wait till the time for the next period, or see your doctor.

But then there are dozens of other reasons for periods to be late.

I agree with chuck. Its totally possible for you to be pregnant and its still too early to test. Or it may be something else entirely causing your period to be late.