hi,my gf had been for a trip with her friend at a very cold region which was unberable for her,she left on 1st of jan and was back on 5th of jan,she said dat something was wrong with her body and she got her chums or her vagina bled on 6th or 7th just little bleeding for a day which is atleast 18 days before her period dates,my query is what could be the reason for it,she now says she got her chums on 25th of jan,m afraid n worried dat was the bleeding for a day cause she might have had sex with her friend or is it coz of some other reason or coz of immense cold weather