Just to clarify, by doing something nice for yourself I dont mean doing anything that could be self destructive. Rather, I'm refering to restoring balance to your life.
Right now you may be spending too much time worrying about and thinking about other people and their opinions and your shrinking friendbase. My theory is that the more energy you spend focused on this, the more it will perpetuate if the problem truly is the vibe you give off.
So you fix the vibe by instead taking that energy and putting it towards self maintenance. Learn to like yourself again, support your own interests, do nice things for people and have your own good feelings from that be your reward. Like I said earlier, dont go so far as to become self centered...just learn to like yourself enough that you dont necessarily "need" external valididation to be happy. In other words...craft your life so that your own care and respect for yourself keeps you from falling into depression and dismay when you're misjudged...and instead offers constructive reflection on how you could fix the problem. Give yourself enough credit to know when you're being misjudged...rather than allowing that negative emotion to take control of you.
By doing this you become more confident, level headed, and most importantly...changes your vibe from draining to refreshing.
Most people wish they were more confident. You can be nervous as hell inside...but if you still go for what makes you happy...in time...you'll be happier...and the number of people who respect or look up to you will climb.
I agree that you may be thinking to much about it...and those thoughts are leading to either actions or vibes that come across as something to avoid to other people.
There is a saying that to find true love you must first love yourself. I used to think that saying was bullcrap but now I understand it. People can love you and will love you even if you don't love yourself...but every relationship...whether it's friends or partners...requires a certain balance in order to succeed long term.
Take my ex for example....she was a big hearted person who met depressed me and wanted to bring happiness into my life. And for four years she kept trying. Problem was...she kept validating me but I'd still tear myself apart when other people disliked me. In time...it became emotionally taxing on her to lift me up when others knocked me down...and our relationship slowly died.
It was only after she was gone that I finally realized what had happened. And that my own depression and lack of self value had cost me most of my friendships and relationships...and even my very life goals and dreams for the last ten years. Without equal parts external and internal validation, I'd grown dependent on other people's approval for my own approval. That's a negative place to be and sets you up for massive disappointment over small setbacks.
I decided I'd had enough. That she was right...everyone was right...that I had to give myself credit...balance my emotions...and learn to be more independent in my self validation. You have to fix yourself before you can invest in other people long term.
I truly hope that helps clarify things.