Why Am I Not Getting Periods for a Month Despite Negative HCG Test?

I advise you to go to a gynecologist immediately. Rashes in vaginal area can be a sign of a vaginal infection or a sexually transmitted infection.
 

It’s completely normal to feel anxious about this. When you don't get your period after having unprotected sex, it’s usually a cause for concern. Stress, hormonal imbalance, or pregnancy could be delaying it. Also, the fact that you took an emergency contraceptive might mess up your cycle. Just give it some time and you may see your menstrual flow soon. However, if there are other unusual symptoms or the delay persists consider taking a pregnancy test.

Fee­ling anxious is understandable. Sometime­s stress impacts your menstrual cycle, causing de­lays or irregularities. If you haven't e­xperienced pre­gnancy indicators and it's only been a fortnight since unprote­cted intimacy, detecting pre­gnancy might be premature. 

If your period commenced on August 9th, it is highly unlikely that it is a pregnancy at this point. Usually, waiting for two weeks after intercourse gives the most accurate test result. A home pregnancy test that detects hCG levels can be used for early detection. Keep in mind that stress or other life situations can also change your cycle. Wait a bit longer and then try the test if you need to. 

Toward the middle of the pregnancy, a smaller belly at 17 weeks might trouble you. If a belly is small, it can be because of the baby’s position, the way your body is holding the baby, or many other reasons. In the majority of cases, it's not a big deal when your health conditions are within normal limits. Continue to eat well and go to all of your pregnancy medical check-ins to ensure that you and your baby are healthy.