I am somewhat reluctant to reply for two reasons: 1) I am battling my own demons and 2) Political Correctness. But I'll give it a try. First, for those of you who do not believe in a higher power, don't take offense.
I believe our level of self-confidence is directly proportional to our relationship with God and Jesus Christ. When we break it down, what we really believe, in a social setting is that people are judging us. There are three things at work in that scenario. First, it is clear your relationship with God is weak or wavering. Why? Two, because if it weren't you wouldn't care one iota what others thought, as long as you were comfortable in Gods eyes and you know you are perfect in his eyes and finally, if your relationship with God was strong, you would welcome others into your life and your presence as they were created in his image just as you were. Just as they cannot judge you, nor can you judge them, because in God's eyes, you are all created in his image. If you are treated less that what you would expect, that is their cross to bear, not yours.
I think the inconsistency in your life could very well be a mild form of bi-polar, or even perhaps something as simple as your bioryhthmic cycle. I happen to play guitar as a hobby. There are times when I am "geeked" to play my guitar, to learn something new, learn a new song. Then I will go a week or two and not pick up a guitar. I know I have mild bi-polar behavior. It is not such that I need medication, but it does alter the consistency of my behavior to a degree. I think when you don't do well at something, your level of interest is low. Plain and simple. The more I'm interested in something, the more apt I am to excel at it. When the interest level is low, I struggle to focus. As long as it isn't something that negatively affects my life or well being, I accept it as "that's just the way I am". If you wish to pursue it further, you could get some blood work done to analyze your nutrient levels, etc. I have found that consistent exercise has created a more consistent "personality" for myself. I'm less moody, feel better about myself, I'm more confident around others, etc.
I too take things personally. When something is said at work that might be meant as constructive criticism, I will at first just let it go. Then I will start to replay it. Then I will pick it apart and convince myself it was a thinly veiled "cheap shot" that they got over on me. That crates a negative "vibe" between me and that person, even though I may be the only one who feels that "vibe" because in reality, they weren't taking a cheap shot and didn't mean it personally at all. Now I've created my own reality that
only exists in my mind! This all goes back to your spiritual beliefs. If you are strong spiritually, then there is nothing anybody can do or say that will stick, because you are already perfect to the One that really matters. You carry the infinite power that can transcend any and all adversity. Remember, Gandhi defeated the British Empire without firing a single shot. It's Power vs. Force. Power is gentle, subtle and omnipresent. Force is limited and only has limited ability.
Regarding the feeling of dread...I'm still dealing with that. That's why I'm here.

But, in those moments when I'm clear, I realize that I really do value life and I really DO want to live. I spent a large part of my life with the attitude of, "Ok, I finished HS, went to college, had kids, they're now grown, so what's left?". And I felt like I was just biding my time until it was time to move on. I was always thinking about death and how I sort of wished for it so I could "get on with it". But I think I'm starting to realize that part of the reason for my recent recurrence of anxiety and panic attacks is because
I really don't want to die! I love my wife, I want to grow old with her, I love my family and I'm really working on seeing the beauty of everyday life unfold around me. But I have to stress, this is
only when I'm clear and not walking around foggy or trembling from anxiety. But I also realize that when I'm like that, it's not the real me. It's not the spirit of who I am. I think what I am going through now, and the things we go through every day, God is molding us into something better, even though it does't feel like it. Think about how good it feels when you're not in that "bad place". It's almost like heaven. I think that's Gods way of telling me, "you don't really want to die".
Again, I have my own issues so I am certainly no authority. But, much like you, I DO analyze my thoughts and behaviors and try to learn something profound from them. And I think I am, little by little. Being able to be completely open with my wife regarding my trials and tribulations has helped immensely. I don't have to be embarrassed or ashamed when I'm in that "bad place". I just tell her "I'm not doing well right now" and she knows exactly what I'm talking about. Just knowing that she's OK with it, makes me fell a little more "OK".
Please remember, everybody on this forum is a little "lost", so I'm not an authority in an any sense of the word. But like everybody else, I try to analyze my own life and situations and make some sense of them. Best of luck. I'm sure you will have some breakthroughs, no matter how small, and they will change things immensely
Ax.
So do not fear, for I am with you; do not be dismayed, for I am your God. I will strengthen you and help you; I will uphold you with my righteous right hand. Isaiah 41:10