Top reasons that is commonly seen in the people who are suicidal are as follows:
The common reason of all suicidal thoughts is depression. It rules our lives even before we get to know about it. People going through depression often hide their feelings and finding them is a tough task by itself. The most common thought a depressed person would have is that “Everyone would lead a better life without me. I am a useless burden on my family and friends”. These are the usual thoughts which corners a person to think that an end to all distress is killing self.
We tend to lose hope when the loved ones do a thing which hurts us. And other common reason why we lose hope is when we fail continuously when we try things which we might have thought that we could easily succeed. The moment when we hit failure we start to lose hope.
I could understand the pain you are going through. Definitely killing yourself is not an option. Stop. Think before you take action. I am not a professional who can help you when you have suicidal thoughts. But I have undergone the pain which you are going through.