Stomach pain, cracked my neck, tension. What shall i do?

Please help me. First, I was very sick but after it went away I was alright for a while. Tonight, I was dropping my friend off, and all night my stomach was really hurting. I cracked my neck and it actually bothered me cause I pushed harder than normal. Then I pushed on my back and my neck was POPPING. What? So I pulled away and then got EXTREMELY hot, and felt almost like vomiting . I took of my jacket and I was in my tee shirt put down my window, and then my air on blast. I live in PA, btw. I had a few minutes to drive home, and the whole way my vision was blurry, too a certain point but I could still see. Then I tried to relax because I thought I was freaking myself out. Then I got a raging headache . I had a pretty bad one yesterday too. I haven t sleep much lately, due to my ADHD meds. Is that what is causing this? Well anyways I got home and my hands felt numb, and my knee caps were bluish and seemed swollen. I have been laying down now, and I still have a really bad headache. Rushing from my eyes to the back of my head. I feel a lot of tension in my neck, too much tension. I am also a singer, so I know when I am sick I still can sing in my high light voice. Right now I cannot do that. PLEASE HELP ME. I feel like something is really wrong with me.