He says he want time to think things over, and I'm at a loss, what to do? I asked him if he already had decided that he didn't want to go on with me, he said no. He just wanted time to think things over and wasn't going to be persuaded either way. This was 2 days ago.
He is asking for space, I would give it to him.
STOP calling him, respond only if he contacts you, with short to the point statements.
You can read the first chapter with the links above. Also start doing all the homework I gave you above.