pregnant or is it my periods ...?

okay i missed my periods the last 6 months the first month i missed i did 3 test but they came back negative 3 times then it was nearly 3 months later so i went to my doctors she done a test and that came back negative to.she told me to come off my pill and id get my periods back in a month or two but at the time i was off my pill because i though i was pregnant and at the time i only started a new pill was only on it 3 days and missed 3 and had sex but the condom ripped.. but that was okay because the fout test came bk negative so im off my pill 6 and a half months now and im going to say i no i was a silly girl but four the last 6 months i was having unprotected sex i only found out you can get pregnant without a period.. did this ever happen to anybody please help .. i told my friend the other day my nipples were sore to touch and she asked was my boobs sore i told her no then i  showed her my nipples she told me my ducks where out  what does this mean.iv camps kinda like period ones in my sides at the bottom of my stomach and lower back .. my boobs areb sore the last two days . the last time i had sex was two weeks ago . this is  ewww but iv been getting lots of dischage that smells and is yellow

sorry its so long

thank 4 helping :-)