What Causes Thick Creamy Deposit On Vaginal Wall?

I have noticed that my stomach is changing i believe ive become lactose intolerant but thats not my main concern, ive developed a thick creammy almost milk like substance in the wall of my vagina and it doesnt seem to go away and its been happening just as long as my stomach pains from milk, is it possible that this discharge is because of my diet? and do you think if i cut out the lactose it would go away... Its not an std or infection doctors have said... i just need to know what to do. Please and thanks