My friend had sexual activity on 12th august. she got her period in august, september and october. but it was lighter than usual so she got a blood test and ultrasound done on 28th october-both were negative. her period was due yesterday-6th november. but it didn't arrive. so she took a home pregnancy test today-7th november, which was negative. she is also feeling some symptoms like bloating, cramps, vaginal discharge, body ache and fatigue. can she be 100% sure that she's not pregnant? or are there some more tests that she can do?