Need teenage advice !!!

So literally my life is a mess right now... A couple months ago my little sister (she’s 13) was diagnosed with a cancerous tumor in her kidney.. it’s been hell for my family and I .. She was in a hospital for 3 months .. I missed 2 months of school trying to help out my family take care of my other sister who is special needs and obviously I fell behind in school .. I recently also lost my two best friends .. they cut me off completely at literally the worst timing .. My GPA dropped a shit load ... My boyfriend I was with for 2 years cheated on me ... I’ve been so stressed and upset and I feel like I have nobody to run to .. or talk to... I have all these feelings locked up inside .. Ive gained almost 25 pounds now .. I feel disgusting and alone .. My family is falling apart .. and I feel myself falling back into depression... I’m trying so hard to push through but I feel like just giving up on everything... I don’t know maybe i’m just being overly dramatic? (I’m a 17 year old jr)