What Causes Dizziness Along With Blurred Vision?

Hi, for a couple days now I ve been feeling lightheaded, dizzy, and my vision will start to blur. I know I m not about to pass out because I ve passed out several times and I know how my body reacts to that. I also have been having pain in my head, almost like a headache, but more on my left temple. If I lay down my head will feel like it has tremendous pressure and it makes it hard to sleep. I ll also get ringing in my ears, or won t be able to hear as well. What could this be? I ve been tested for blood clots and don t have any, but I also have high blood pressure and I m only 20. Any ideas?