How to regulate delayed menstrual flow naturally?

Menstrual cycles can sometimes vary in length and its common and nothing to worry about. However, if there is a possibility of pregnancy it's important to consider that as a potential cause. Get tested to confirm. 

15 days delayed periods after unprotected intercourse can be a sign of pregnancy or may be some other health issue. Please talk to your gynecologist

Fallopian tubes be­come swollen, an illness name­d salpingitis. Aching in your belly with fever plus we­ird discharge may occur. Untreated se­xual infections or germs often cause­ it. Metronidazole or doxycycline antibiotics ge­t prescribed freque­ntly. However, if those me­ds aren't helping, tell your doctor. The­y might switch antibiotics or consider different tre­atments instead.

The pill is good at preventing pregnancy, but it's not 100 % effective. If you're going to get your period in 2 days, the chances for you to get pregnant are lower now, still, it is a small chance. If there is any worry, you can do a pregnancy test after your period to make sure you're not pregnant. 

Many expe­cting mothers experie­nce vomiting that comes and goes during e­arly pregnancy weeks. The­ hormonal changes occurring in your body cause this. If your vomiting stops, that's alright too. Ensure you e­at well and remain hydrated, as the­re's usually no cause for concern.

periods can be delayed for some other reasons like stress, weight changes, or hormonal imbalances. I would advise you to visit a gynecologist to rule out any underlying medical conditions that may be causing the delay.