Definitely u have had a lot on ur plate of fate so far. But it is difficult to say whether all these have been cause or result of this kind of psychological state...
The fact is that definitely there have been some positive events in life but being in this state has disabled u to not perceive those things as u wud have otherwise.
This can be done wid long psychological training and some medications for few weeks. U will appreciate the change definitely but only if u move and seek help from a competent psychiatrist.
Hope this helps u but feel free to consult further. Take care