Started bleeding for one day but the bleeding stopped and now spotting. Never been on birth control. Took pregnancy test negative. Came two days early?

Don't know reason. The main reason for light periods is a change in hormone levels. Causes for what seems to be a light period can include: implantation bleeding in early pregnancy, thyroid problems, eating disorders, excessive exercise, initial periods for a girl, use of an intrauterine device, oral contraceptives & perimenopause.
Spotting. Your spotting may actually represent your period. See what happens next month and if you are still spotting consult your doctor.

Related Questions

Miss my period because I change birth control. No withdrawal bleed in two weeks. Pregnancy test negative. Now having painful intercourse.

Painful sex. There can be multiple causes. Dryness is one of them. More time to foreplay increases lubrication of the vagina. You can also use water based lubricant. Also decreased estrogen in the blood increase dryness of the vagina. You can get that checked. If it is low estrogen hormone supplement can help. Another cause is vaginismus which to treat is much more difficult. You need to see an expert gyn. Read more...

Been having vaginal bleeding for 27 days straight what can be the cause? I'm on birth control, pregnancy test negative, waiting on sonogram results

Stop OC . Stop OC for 3 dYs and start again.If this doesn't resolve then go get an exam to see wether there is some genital infection or lesion causing the problem. Read more...
Hormonal abnormality. The causes of dysfunctional uterine bleeding are either hormonal or structural (like a fibroid). At your age I would strongly suspect a hormonal problem and not a fibroid. The ultrasound will rule out (or in) the structural abnormality. Do you have PCOS? If the ultrasound is normal your doctor will likely run multiple tests to determine what the hormonal problem is. Read more...