You've been dating only 2 months. Her behaviour sounds consistent with a together, busy woman. Have you considered she was simply respecting the privacy of your time with your son? In her shoes, I would *never* presume to intrude on father-son time, even by sending a message. It was only a few days, she sent you a message when she knew you'd be back. What more do you want? She seems to respect you are an adult with responsibilities that don't always include her.
You need to grow up and, yes, you seem needy. I wonder if this is what your ex told you when you split? You run the risk of turning off what sounds like a potentially good woman if you keep down this path. Good luck.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh