Feeling Isolated and Alone After My Mom Left

I’ve been having a lot of trouble with my family recently. We used to be very close but since my mom left with her boyfriend to live in florida, she’s kinda kept my brother and I to fend for ourselves. She only ever wants us to fly to her, but never wants to do the same for us. When I’m here though, I feel very isolated and alone because the community here is aimed at a much older crowd than me. I’d been feeling suicidal and on edge since before I came here, and the isolation and lack of effort has made everything worse. Granted, I know my mom tries but she just sees me as ungrateful. I’m an extrovert and my brother is an introvert, so feeling alone is very very difficult for me, especially with my BPD. The only person I have right now is my boyfriend (who has also been my best friend for years). We got into a fight over dinner (me against them) because I wanted to go out after MY BIRTHDAY DINNER. So now I’m just alone again and I have no idea how to snap out of any of this.