Hi Everyone!

I think I am trying to write (on history), but every sentence I write seems garbage to me. This is my final year, I am pushing myself so damn hard to finish my work, but I am constantly devastated by distractions. My problems are basically;

1-I can't seem to remember some vital, general details, although I thought I have known very well.
2-I constantly see other people's work, who worked on similar topic ( although I know mine will be very different from them, I know this is social science, I can't help but feeling hopeless, insufficient)
3-Although I write stuff, I fell its useless
4-I have an absent supervisor.
5-Time flies, I feel I am falling apart. I am totally lack of self-confidence.

Help!