I am so sad and i dont know why?

ive been sad or 3 months. and the only time im ver happy is when im with my boyfriend, which is only once a week. we fight alot because of stupid stuff, and the more we fight the easier it is to slip into a fight. so we finally made up and its been a day and i should be happy. but i cant be happy. another thin is my old best friend of 13 years just texted me saying i was a freak and a scared her. i told her i wold try harder and stuff but she finally accepted my apology when it wasnt there so i havnt been talking to her for about a month and a half. i think i started cutting myself about the same tie she left me. her and my boyfriend bth cotried i guess. she tried talking to me last night but she also cussed my byfriend out and said he was a waste of space and made him cry. my new best friend hates her because of what she did to me. and now my an my old bestriends step mom dont like eachother even more. shes a ***** and wouldnt let my old best fried hang out when me and my boyfriend were together because were a bad example. were 15. i think im old enough o have a boyfriend. sorry if your against it but this is my first serious one. dont be to judgy on my boyfriend cuz he has depression and is bipolar, but i still love him very muh and its just who he is. alo my old best friend just treats guys like **** and was always constantly trying to get me to dump my boyfriend. i guess all of this is why im so sad. imy boyfriend helped me stop the cutting, and ive havnt cut myself for 2 weeks but i still cry everyday... i feel hopeless all the time. i think i might have depression ebcause i have 8 out of 10 symtoms. i tried talking to a online theapis but she got me pissed. idk i guess im kinda laying it all out in front of me. and im also broke so that contribute to everything and m moving into a small 2 bedroom house with 5 people. so idk any advice i guess?