You can get pregnant eve­n a week after your pe­riods. This happens due to ovulation - egg re­lease from ovaries. You might the­n experience­ missed periods, tiredne­ss, and nausea if pregnant. Using protection during intimacy lowe­rs pregnancy risk. 

The symptoms you have mentioned are caused by hyperthyroidism. These imbalances can affect your period too and result in what you explained. You need to talk to a doctor about these signs so that they can suggest treatment plans and also ensure that your levels of thyroid are being properly taken care of.

A pregnancy may take place if the semen comes into any contact with the vaginal area, whether there is a penetration or ejaculation. It is imperative to have barrier protection while engaging in any type of sexual activity because this way you and your partner will be prevented from having unwanted pregnancies and from contracting sexually transmitted infections.

In this case you should go for second opinion of another experienced doctor. They can evaluate your case and then you can come to a conclusion.

You may have vaginal infection, which manifests in the form of itching and white discharge. It is advisable to see a gynecologist that will identify and manage your condition in an amicable way. Also, it is recommended not to use any aggressive soaps or perfumes at the genital and follow good hygiene rules.

The first thing you should do is to take a test. Should your test result as positive, arrange for an appointment with an obstetrician/gynecologist (OB/GYN) promptly. If the test result is negative and you see that your period of menstruation still has not started by the end of a week, you should also visit a doctor to establish the cause of the delay.