Hello :)
What you say you experience there is a good thing, really. You begin to see yourself objectively.
Now, you either choose to victimize yourself - and go on a downward spiral, or you decide to take the hard way up and do something good about it - discover who you really are, beyond the "garbage" in your mind.
I wish you the best of luck!
There's no straight recipe to find out who you really are. Everybody will tell you what to do based on their own experiences - but only you know what will actually work for you. And if you don't know yet, you're the only one who can discover it.
Some meditate, some do Tai Chi, some travel the world... some knit or do pottery or go minimalist.
All I can say is try to do things you like or feel attracted to, even if this will seem to be - for a while - nothing more than a series of trials and fails. And try to hear your own voice, despite the noise in your head.
If you persevere, you will succeed, eventually. Enjoy the ride! :)