I can relate a lot to what @entheos
said about making a conscious decision to change. As with anything, that first step is realizing you need to change - admitting you're not happy and what you have been doing is not working for you. That's also a first step to seeing your ego and how it's no longer helping you navigate reality, but it's reducing your functionality and detaching you from experiencing it. The ego says "this is just who I am!". It's limiting, of course, and it often points the finger at others when it doesn't get results it likes.
I can't say I'm 100% over fears of being a burden. It still pops up at times, often unexpectedly & just when I think I'm over it. I'm a child of divorce, and that's part of my explanation for it. The difference now is I know it's not true, and so I can choose to not act on that emotion. I know it's just leftover, emotional noise from my childhood.
So one thing to consider is projection. If you fear being a burden, you may also fear being burdened. If you fear being too much for others, you may fear they are too much for you, aka you don't have enough within you to handle them (a kind of paradox...to much for others and yet not enough for them). To help ease this, give to others emotionally. The short of it is giving what you'd like receive from others. Don't dismiss others as needy, dramatic, to sensitive, etc. The less you dismiss others, the more you may lose the fear of being dismissed (aka being a burden). If you fear people separating from you for being "too much" and seek to be, say, invisible or extremely agreeable so as to be connected...you are already disconnected. That connection is an illusion. Withdrawing to not be rejected is rejecting others.
Another thing to consider is dealing with "thawing out" emotionally, or "de-numbing". Kind of like waking a sleeping foot or literal growing pains, it can be uncomfortable and awkward when you start to wake up emotionally. It can be downright painful even. The important thing to remember is that it is temporary. It may have debilitating effects, for a time, but it's part of becoming more
functional. Just let the emotion pass over you, don't turn it into thoughts to dwell on. I used to think analysis was solving stuff. But you usually already logically know what is true; you aren't a burden, you have things to offer people as a friend or partner or whatever. So let the emotion pass without giving it more weight than it warrants. It's usually about a past experience you never fully processed, not the present. Present emotions are pretty easy to process....they arise in relation to what is happening and then subside once it's over.
Remember that emotions are very physical. Getting more in touch with your physical body can help facilitate emotional processing.
A lot of advice will tell you to do meditations where you just breath and focus on releasing tension in your body, letting any thoughts pass by and refocusing on your breathing and releasing tensions. What this does is connect your conscious mind with your body sensations...all of a sudden, the noticing of a tension may make an old emotion arise. It will be something like an epiphany. And with that release, you'll find yourself mostly over it. Whatever used to make it arise won't ruffle you so much anymore. Analysis doesn't usually bring this about...it can actually made you dwell and feed an emotion. There is some legit science behind the gut being something of a "second brain" and "storing emotions" in the nervous system. That's what you need to address.
Also, emotions are often in response to thoughts, which then fuel actions, give certain results, which our thoughts then interpret, and then we respond emotionally, etc. It may seem backwards, but start by changing your thoughts (including perceptions), as well as some behaviors. Perhaps start with thoughts about yourself - be really aware of negative internal dialogue about yourself. Counter it with something realistically positive. I started with a kind of personal mantra to "be nice to myself". Don't say anything to yourself that you wouldn't say to a friend, and remember to be the kind of friend you'd want, including to yourself. When you start cultivating more positive mental and emotional experiences, then behaviors shift too, even if it's just vibe, and you get better responses from other people. It's a positive cycle. Be aware of your emotional story - the way in which you frame everything. It helped me to write down my "old emotional story" and then write a new one based on actual events & words from people, so that it wouldn't feel like a delusion. Then begin approaching reality with the new emotional story. This new framing will change how you see yourself and life, and that will change how you act, and again, you get new responses which reinforce this.
Also, this stuff is often two steps forward, one step back, so be patient and compassionate with yourself as you grow. Awareness is a big step because you learn from mistakes more rather than repeating patterns. Every little change you make is altering a part of the pattern, and as you alter more & more, you're creating a new pattern of behaviors, thoughts, feelings, and ultimately, emotions. Instead of burdening people with intense, dark emotions, you can gift them with not only pleasant, lighter emotions, but also the empathy and insight that comes from having overcome heavier things. You also give people permission to be their whole selves. Vulnerability in people often looks courageous, not weak, and it's often liberating and inspiring, not a burdening to others.
I hope some that helps! Your post was really articulate and definitely resonated with my past experience, so it seems you definitely have the emotional intelligence to become who you need to be to live life more fully.