Er, not sure I understand your question, but just in case I'm close, an opinion.
You can't really "rule out" any of it. All those possibilities can influence the others. Sure, it is easy enough to get some organic data, so do it. It won't answer everything. Sorry to inform you but there isn't one simple answer to life. It's cumulative, both physically and emotionally. You teach yourself how to react to events...and it becomes a habit. If you teach yourself that everything's just getting worse, it probably will be. The same circumstance could happen to 10 people and I bet there will be 10 reactions/outcomes.
You keep mentioning you need to talk to someone. Do it. They can help you recognize and even unlearn habitual thinking.
There are no neatly packaged answers. Instead, it is a pile of wrapping paper with a bunch of knotted strings attached.
Hmm, guess that little analogy proves that I must be preoccupied about relatives' Christmas gifts!