there is nothing called vampire. it is all stories and people do cash it on its name. dont get fooled by it. your problem is usual, as you are ientering the teenage group the hormonal change will have very much effect on your thinking also and if you land up in these kind of unrealistic thoughts it will harm you. these are normal in the young life. you need to get over it. there is no vampire as such.
You need to get your IRON and Blood Levels checked. Do these feelings happen when you are on your period or near your period? Regardless signs of tasting dirt or copper/blood and cravings for dirt/ blood can be an indication that you IRON cound if VERY low or your Hemaglobin which is apart of your red blood cells. When was the last time you had your blood levels checked?