But in order to beleive that evolution is true, you must beleive that the first thing that ever existed came from nothingness.
What about "The diversity of life on earth is best explained by changing allele frequencies over time" do you feel relies on "the first thing that ever existed came from nothingness"? I don't see the connection, but then, I'm using the definition of "evolution" that science uses.
I cannot conceive of a universe in which everything started by accident from nothingness.
That hardly has anything to do with anything. It may be that the universe is stranger than you can comprehend. The question is, what does the evidence point to?
To take God out of the picture means that everything literally came from nothing.
That's what you get with God
in the picture, too. First, God has to come out of nothing, then God has to make the universe out of nothing (how? by magic?). Sounds like you've just pushed the problem back one step.
The truth is, we don't know what's outside the universe, or how universes come to be. The idea that there's nothing outside the universe is merely your own assumption.
If you find the thought of a god or gods impossible then evolution becomes your only option, with all the other ethical and moral baggage it brings with it.
I don't find the idea of God impossible, just inconsistent with observation. If you put God in the picture then you have to deal with the fact that the only God that could exist and allow things to be as they are is a god who is either amoral or powerless. Neither one of those seem like gods worth caring about.