I hit my head on the sidewalk and got a really bad black eye from it. Half of the white part of my eye is solid red do I need medical attention?

Red eye. If there is no blurry vision or eye pain, you may just have a sub conjunctival hemorrhage and can give it time to resolve. If you have blurry vision, eye pain and/or light sensitivity, you may have ocular inflammation (uveitis), and should see an ophthalmologist promptly.