How to ask for help?

So I've battled with mental health issues for 5, almost 6 years now. I suffer from depression and anxiety disorders. I used to self harm a lot several years ago but since then I have been able to almost stop completely. My family is aware that I was struggling but nothing was ever really done to help me. We basically had one discussion about my mental health and since then we avoided the topic. (this was 3 years ago) Recently my mother and my sister have been prescribed meds for anxiety. My mother also takes antidepressants. To be completely honest, my mental health has worsened because of this. I feel like I wasn't worth the effort to help but when it's other people who are struggling they receive the help. I know I'm getting worse again. I've been thinking about self harm a lot recently. I just don't know how to ask for help because I feel like nobody will care.