What Causes Dryness In Vagina?

I am a 30 year old female, I have one long term sexual partner.
I have recently undergone a high amount of stress (I had a final exam for my masters degree to study for) I have noticed that my vagina became very dry. I used to have a very moist vagina and normal discharge throughout the month but now I have nothing. I have now sat my exam so life is back to normal but I still have dryness.
Then I thought that I hadn’t drunk as much water as I usually do (normally drink at least 2 litres each day and have healthy diet with nuts oil fish and low fat, fruit and veg, no junk food etc). I have increased my water intake. Today I think I have a urinary tract infection because I feel as though I need to urinate even after I have just been.
At first I thought the dryness could be because of stress but am now wondering if all symptoms could be linked. I had a UTI about 2 months ago but no dryness occurred and discharge was normal.
I had a smear test recently and the results came back normal