Glad to hear that. Yea, it's a bit of a gut shot - some pain, then anger, then acceptance, and then, as someone else said, back to work; The 7 minute YC rejection workout.
The network is freely available. You could email sama with an honest question as a startup founder and you'll probably get a reply. He genuinely loves helping people.
I don't know what "Your network is your net worth" means, but it sounds like a worldview in which the people you know matter more than what you can do. That's sometimes true, but none of the major startups started off by networking. It didn't matter who the Google founders knew. It didn't matter who Zuck knew. What mattered was what they were doing.
The only reason investors might be interested in you is if you're starting the next Google or Facebook, because their entire business model depends on it. But there's an optimistic way to phrase that: If you're starting the next Google or Facebook, then who you know doesn't really matter.
It's depends where are you. We are in Latin America (invited), we are so far away to have any chance to create a great network from here, and moving to SF (or any place in USA) first without a network is almost impossible and very expensive for us.