I miss his hugs, his kisses, his laughs, his cries, his Joy. Now that's complex and scary stuff. Your feelings are about your son are absolutely right on the mark. All parents should feel this way about their children. I'm glad to hear it, and I urge you to stay that way.
Violence is never, ever the answer to any problem.
The two of you started a relationship when you were young and financially unstable. You're hardly the first to do so, and you're also not the first to add the emotional and financial burdens of a new child. Under these circumstances, even the sturdiest of relationships will stumble. If, however, your ex refuses to see this and doesn't agree that her son should have a loving father involved in his life, then you unfortunately must take legal action. I know this is scary because you don't think you'll win.