Thanks for writing.
If you miss your period, the first thing you need to do is a urine test for pregnancy
Yellowish heavy vaginal discharge
can be due to infections of the vagina. Foul smell and itching are generally associated with these infections.
Abdominal cramps and spotting can also occur.
Genital infections can cause delay in your periods but before keeping this as a possibility you need to rule out pregnancy.
For diagnosis and proper treatment of genital infections, it is a must you consult a gynecologist for an internal examination.