Three points to ponder about: (bold for emphasis, no yelling intended)
First: Prove me, that you
do exist.
Second: Your brain acts 250 milliseconds
before you are
aware that you want to carry out any action.
Third: What exactly
do you perceive when you see something, or hear something?
You may want to read up on solipsism, radical constructivism and for starters on the Allegory of the Cave by Plato. (You might want to get started with the Metaphor of the Sun and the Analogy of the divided Line on which base the Allegory of the Cave needs to be interpreted.)
For your reasoning:
1. Something can not come from nothing.
- Exactly why?
2. I exist.
- See my first point.
3. Therefore, someone must have caused my existence.
- Perhaps it wasn't some
one, but some
thing that caused your existence, no?
4. Either I caused my existence or someone else caused my existence.
- Void, if you can't prove that you definitely were created by some
one.
5. If I caused my existence, there is a designer; if someone else caused my existence, there is a designer.
- See above.
6. Therefore, there is a designer.
- Fallacy. (Yeah, I'm horribly blunt here, but I simply don't agree on the aforementioned points.
)
There are two sentences in your post where I believe you are dead right. (At least the basic idea, there is much more to follow up these assumptions, which I will clarify when I elaborate my three points. I'll wait with this, it is way more rewarding to figure it out for yourself - I know it busted a couple of misconceptions for myself. Note: I don't want to be parenting, just getting excited about everyone who starts to tackle the really important questions
TM.)
"This means I doubt that what I perceive exists outside of myself. That doesn't mean I think or know other things don't exist, it means that I can't know that they do exist."
Really good start. If this genuinely came from your own pondering - kudos, I needed guidance for this.