At first i bleed a small blood stain.next day when i wiped it was brown with come clear liquid.the next day was pink redish. period?sore nipples too

Difficult to say: The first thing to find out is whether or not you are pregnant. If this is not the case, then this could be the beginning of a normal period (some women get this kind of light premenstrual staining every month). If you do not have a normal cycle this month it could be that you did not ovulate this month. Many causes for this including stress - and it will usually return to normal within 1-2 month.