Sharing Our Innermost Thoughts

hello please help im sad im really sad im crying my girlfriend is really good girl but iam a bad boy i love her so much but i think her wrongly i always misunderstood her my heart has 2 side one is she is good another one is doubt one always think wrongly about her they both fight inside me i cant . 9 days she stayed with her whole family her cousin who is a bad guy now behaving good with her that 9 days she cant able to talk with me because her family memebers dont know it but she tried and called me serval times she said that her cousin was so helpful and fun he is one who talks good to her she talks like he talks (slang) but its hurting because she doesnt have male friends im the only one she calling him(cousin) with a nickname(not my nikename) she always use nickname to me she said he tried hard to make her laugh unfortunately icant go to her home and i cant call her .now i spoke that he and she had a realtionship go to him i think she got hurt but she whenever she is telling about him its hurting me because she always be like that only to me im 17 years old im so sad am i a bad boy? but she is very good girl. she also talking like me with worry to make me understand i think but she is very good girl