You are likely to be having a bacterial infection of the vagina called Bacterial Vaginosis. The other possible causes are a yeast infection or if you have a history of unprotected sexual exposure an STI like chlamydia or Trichomonias.
Since you are having foul smelling odor, bacterial vaginosis is the most likely cause.
You can use Intravaginal Lactobacillus capsules. You can get this from the pharmacy without prescription.There are several brands available, these help to replenish the good bacteria in the vagina and thus to get over the infection. You can use Dr.Formula's Nexobiotic or FemDophilus Women's Probiotics. These brand names are ***** ***** many other brands are available and you should discuss with your pharmacist about good brands.
An application of Over the counter CanesBalance BV gel twice a day.
Also keep the area dry and clean. Avoid using any vaginal douches.
Sexual activity should be done with condoms for at least two weeks. Use of toys etc should be minimized or done with condoms and strict sterility.
You can try with this, however if the symptoms persist for more than a week or get more severe, then you have to approach a doctor.
You will need prescription antibiotics like metronidazole or clindamycin. The treatment is fairly simple.
Hopefully these steps will resolve this situation quickly. However if the problem persists do see your doctor.