I'm a week late on my period how should i be feeling?

Missed period: depends on what you mean, if you think you are pregnant take a home test

No one set of feelin: If you are concerned about signs of a pregnancy regarding a missed period, there is no one set of sign or symptoms that everyone experiences. Some women experience nausea and/or vomiting and some don't. If you are really concerned about a possible pregnancy then I would advise that you take a home pregnancy test to check.

Probably as usual: Not uncommon to have irregular menses at your age, however, do a pregnancy test if this is a possibility

This depends: Is there a chance you could be pregnant? If you are sexually active, then a home pregnancy test makes sense. If you are not typically late, and you have had sex with a male, even if there was no ejaculate but unprotected penetration pregnancy is possible. If you have irregular cycles then this may simply be due to that. Find out either way with a home pregnancy test. Best of luck!