Good day, i have missed my period but pregnancy test came out negative, i have cramps on my pelvis, especially the right hand side, with neusea. what could be the cause of this?

Other causes are...: Pregnancy is the most common cause of a missed period. If not pregnant, other causes of a late or missed period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (especially birth control pills), hormonal disorders, etc… A visit to one’s Ob-Gyn doctor is a good idea if symptoms are persistent, recurring, or worrisome.