Hi! should i see a doctor about bright red spotting instead of period and negative pregnancy test one week later?

Not necessarily: The main reason for light periods is a change in hormone levels. Causes for what seems to be a light period can include: thyroid problems, eating disorders, excessive exercise, initial periods for a girl, use of an intrauterine device, oral contraceptives, perimenopause ; implantation bleeding in early pregnancy which rarely occurs. If it keeps up - let you gyn know.