It sounds like you have BV , ( Bacterial Vaginosis) which is a bacterial infection that is caused simply by a change in the ph balance in the vagina. This is NOT an STI.

There are many ways to treat this , from using simple gentle acidic douches ( apple cider vinegar ) to raise the ph to a more acidic level, or by inserting the chewable high dose vitamin C pills into the vagina at night when sleeping.
There is also a new product on the market here in the uk that is a gel that redresses the ph balance and cures the condition.
Do try and avoid using antibiotics to cure it. It cures it , but only makes you more susceptible to the condition in the long run.

Good luck . I know exactly how this feels.