One thing I notice in your post, and I speak merely from my observance and experience. I won't say it's exclusive to females but I can say that it's only females in my experience that do this so far.

What I see happening here and why you may feel "worthless" currently is that you may be piling up "proofs" into one big mound of "you're worthless" thinking. In other words what I see happening is your becoming overwhelmed with these things and mashing them together into one big ball that just rolls over your emotions making you take it all at once.

I have noticed this with many of the women I've been with that when they feel overwhelming feelings of negativity that typically if asked they will give you a list of things that they are currently thinking about. Usually unrelated items. Typically taken one by one mean very little or sometimes nothing related to the overwhelming emotion.

I can't say for sure but can you ask yourself, is this what you might be doing?