I'm kind of weird with blood

With other people's blood I'm fine but if its my own its different. If I just get a cut or something than I have no problem with it, but when I go to get blood work I can't look at the needle in my arm and I can't look at the blood flowing out of it. Whenever I get it done I get really light-headed and I have to lay down on a bed because the first time I got it done I almost fainted
Also if I see blood on the ground or something than I'm fine with it, but I can't think about it flowing inside of my body. Just typing this is making me feel sick

A few days ago I was in psychology class and we were talking about blood flow in the brain and I got so light-headed I had to put my head down on the desk because I thought I was gonna faint. After a while I started sweating and I had to ask to leave the room because I thought I was gonna be sick
Oh and after class I talked to my friend and she said that during class she looked over at me and she said that my face turned so pale that my skin looked blue
