If you think that there is some objective morality that is inherent to the universe, the burden of proof is very much on you to show that, not on me to disprove it. (But if you need a disproof, here's as close as I can get: I am 100% certain that you cannot give a definition of "morality" that both meshes with what's expected of the term and that implies the existence of some fundamental objective framework for determining what's right and what's wrong. Just think about it for a while.
Or, alternatively [and not equivalently, but evocatively]: we're all just particles. You can give any brilliant argument you like about the morality of an action, and my particles are just gonna keep on doing whatever the fuck they want.)
As you discuss, lack of objective morality is horrible. It still makes me feel weird when I think about it, and I decided that "ethics" was bullshit when I was thirteen. My brain is hard-wired to believe that certain actions are "right" and certain actions are "wrong" in a sense that encompasses more than just my brain's response to those actions, so thinking about (what I see as) the truth about morality causes a dissonance between my conscious and my subconscious.
In the same way, my brain believes very deeply that everything has a cause, so it believes that there's a meaningful answer to the question, "Why does the universe exist?"
But that question doesn't have an answer. And objective morality doesn't exist. Sorry.