IBecause of the increased amount of discharge and foul smell and in the absence of other symptoms, it sounds like a vaginal bacterial infection, (which BTW is quite common)
You need to see your doctor or gynecologist to take a vaginal swab to have it tested.
There are not a gazillion tests to be done. This should be a straight forward case so it should not cost you a fortune, lol!
If this is the case indeed, you will likely be prescribed oral or topical antibiotics.
Hope this helps, however, my comments are not intended to replace medical advice.
I agree with Lightseakers response. It sounds like a bacterial or fungal infection. If you can't afford seeing a gynocologist then go to Family Planning. They can test you. I wouldn't wait . PID pelvic inflammatory disease can have permanent repercussions if you wait. Besides who wants to have a smell others might notice. Every woman has experienced something like this so don't be embarassed. Also be totally honest with your physician or PA. They need to know everything so they can help you.
I know this sounds crazy but it works, get you some Garlic gel tablets ( can find in the vitamin section) insert one into your vagina as far as you can, do this everyday until symptoms are gone.
it could be BV which is a common imbalance of bacteria http://patient.info/health/bacterial-vaginosis-leaflet - get doc to check you out its always best to be checked