Welcome to the board! This is a great question!
DS is 17 months old, and I still deal with the trauma regularly enough to mention it. I'm finally to a point where I don't cry every day, but I know I cried daily for at least a year. I think about it a lot, especially when I see other PG women or babies, and Christmas songs really don't help. (I bawl every time I sing Silent Night because I just think how awful Mary had it in that stable...)
My best advice is to find a good counselor, one with lots of experience dealing with trauma victims and grief. See this counselor as much as necessary. I went bi-weekly for a while, then started lengthening time between appts. until now I only see her every few months when I feel like I can't handle it all. I haven't needed meds., though many women do, no shame either way; people need what they need. But my counselor has given me numerous strategies to deal with all the stress and emotions. Most are simple things that I just wouldn't have known to do without my counselor's guidance, but they help so much!
Also, ditch the time frame for healing. We all heal differently. And telling yourself (or listening to others with good intentions but no actual expertise in this topic) that you "should" feel any way at any point in time is probably the worst thing you can do. You feel how you feel. You can deal with the feelings many ways, but you cannot stop yourself from feeling them. A counselor can help you learn to acknowledge and channel your feelings in a healthy way.
Best of luck! And please come back often for support.