Metallic Taste In Mouth, Nausea, Lightheadedness, Headache, Backpain, Runny Nose, Sore Throat. Reason?

Hi , I m getting a very bitter strong sort of chemical like taste in my mouth and it feels as though it s coming from my throat. It s so bad, it makes me gag and i feel as though i will throw up! I ve also been getting lightheaded and feeling sick throughout the entire day with the last few weeks. I get alot of headaches and backpain , runny nose and sore throat every morning and night. I Don t understand, they all seem to be pregnancy symptoms , But theres no way i can be pregnant As iv e gotten my period normally and am not getting sick in the mornings and if i was pregnant i would have more of a belly than now as it has been 12 or 12 weeks since i had unprotected sex and he did not ejaculate in me. Please help.. I m only 16 and i dont know what to do.