Hi, damaged, I'm sorry to hear that you're not doing very well.
I'd like to say that being depressed and not feeling fine are health issues which need to be addressed. It doesn't mean that you have a serious mental health problem.
It sounds to me like you're afraid of being labelled by having a mental health disorder. Please don't be afraid of the evaluation. It's harmless.
Depression is a real illness; please not the word "illness". It's a debilitating illness that can disrupt your life like any other disorder i.e. diabetes, parkinson's, etc.
You will probably be asked many questions, perhaps asked to take a survey which will have multiple choice answers, or maybe a ink spot test (someone will show you pictures of various ink spots and ask you what you see and you tell them what you see in the picture).
It's encouraging to read that you have happy times also.
You've already identited that you have been sexually abused, and perhaps, this is a good opportunity for you to embrace this evaluation with a hope of ending your depression for once and for all.
I hope you're not afraid, and if so, I'm here for you. I'll try to ease your worries, if I can.
I wish you luck, and I hope that you're well!