Hey Restless,
Just read this post and thought I'd share my opinion on the subject of being vulnarable and insecure.
I've been insecure and lonely since age 7, shared some things on here that could be thought off as the "cause" of my loneliness, truth is though that my loneliness in adult life stems from my anxiety and in a way unwillingness to be vulnerable, when we open ourselfs up to others one off 2 things will happen, we either get accepted or we get brushed off, ignored, "ghosted", when too much of the first scenario happens you might develop insecurities and as a result you could stop allowing yourself to open up and be vulnerable ever again.
The fact that you're feeling vulnerable means to me that you tried and failed, this is also exactly what I think I myself and probably allot of people here should do to break out off isolation... Without opening ourselfs up to hurt we will not make any meaningful connections in life.
It all comes back to that one simple fact for me, whatever your problem is in life, you'll never overcome it if you don't learn to take a risk and deal with whatever the outcome may be.
I'll stop the lecture now, turned out a bit longer as I initially imagined it to be, my point was simple, you failed this time and are dealing with the effects, but atleast you are trying!