Hi there,
I'm sorry that you're not feeling well :(
I think you're right about the vaginal soreness and discomfort possibly stemming from lack of intercourse this year. You could take an over-the-counter pain medication for the soreness meanwhile; the pain should subside soon after...
The bad body aches, killer headache, and nausea sound a bit more serious. Have you taken anything to help with the nausea, such as Kaopectate or Pepto-Bismol? You should try either of those to help settle your stomach and relieve the nausea. Be sure to stay hydrated, with water especially, and ginger ale if possible ~ don't chug it, drink slowly. If you think that you might be able to eat, start with very bland food like saltine crackers or toast. Get plenty of rest and take it very easy meanwhile. If you don't see any improvement, or if your symptoms worsen in the next 24 hours, I would suggest seeing a doctor right away.
I hope you start feeling better soon,
Take Care