I feel bad that I'm mean to people I care about when I'm suicidal.
That sounds hard to deal with. Is that your way of coping with your feelings?
People mean everything to me when I'm suicidal.
If they mean so much to you, you should try to be nicer. They can be a great help in getting you through those suicidal thoughts.
Why do I need their help if I'm going to kill myself anyway?
It's important that you let people help you overcome the feeling of wanting to kill yourself. It can be really hard to deal with a situation like that on your own, and I'm sure they wouldn't want to hear that you had gone through with killing yourself.