you must immediately go a obstretics/gynecologist doctor .they will get a blood test
done to know if you are actually pregnant, before its too late for the abortion
, since you mentioned that you are just 17.sometimes the hcg hormone we check by the home pregnancy
kits is not sufficient enough to show. however sometimes irregular menstrual bleeding is common in age group below 20 years.they can also check your thyroid ,pituitary gland
and ovaries for some hormonal problems.