C-PTSD Symptoms. Pls help me with it?

I had Moderate Depression and was advised to take Mertazapine. However, am not feeling better. Its more worse. I keep hurting myself and cant sleep at all. Its been 3rd night am awake. Feels like am re living the same situation in more worse way. I dont know how to react, what to say, lost feeling, poor concentration, bursting out anger, negative feeling about my future, extremely and frequent mood swings, avoiding social life, extreme suicidal feeling, guilt. I find myself in the middle of no where, helpless. I cant talk to my parents as they might not take this seriously. They are planning for my marriage and I dont think its right time with issues like this. I feel my life is reducing day by day. Tremendous headache. And the worst part am having a complicated relationship where my marriage thing am not sure. However, am really not willing to marry now but its very difficult to convince parents on same. I feel like shopping my hair off. Irritaing! Can anybody pls help me with it?