bipolar advice ?

hi I'm 15 and have a 20 year old sister who has bipolar. i thought i would look up the disorder to know what to expect, but reading some of the symptoms i realised that i get some of the symptoms, but only some times during a week and i never really know how i feel, i have had issues in the past and ended up trying to kill myself, i was seeing a conciliar but always felt either confused at what she was saying or like she didn't really understand me. im almost always wanting to be alone in my room and i don't really like hanging around with my friends as much has i used to.i have also lost interest in most things i used to love and if i go to do one of the things my mind seems to go blank, i also never got on well in school and always felt like the failure. it would be nice if some one could help me and tell me what way to go about it or if im just being silly.

yours thankfully

nikki