If you're vagina feels itchy that's a common symptom for yeast infection which you can treat buying an over the counter vaginal cream at any pharmacy or even walmart. The cream is moistant
One thing that can help is to keep that area dry and use lose fitting clothes at bed time
I wouldn't go to the er for what's most likely a yeast infection. Go to the drug store in the morning (or now depending on your time zone) and get some over the counter monistat. You can always call your doc to be seen sooner just to make sure that's what it is.
Put plain yogurt does wonders