Your question: "I took a pregnancy text after I was supposed to have my period and it was negative... But I've been taking a lot of vitamin c and I feel somewhat nauseous is this normal? Am I pregnant I'm only 15 bit I took the test 2 days after my missed period"

You took the test too early. Pregnancy tests are most accurate 2 weeks after a missed period. Taking too much Vitamin C can cause these issues as well.

At 15 I hope you are NOT pregnant. However without proper precautions you may be soon.