I have found that one of life's hardest lessons for us to learn is this: Bad decisions always have bad consequences.
In other words, when we act foolishly or do something wrong, we always pay a price, and our lives will never be as happy or as stable as they would have been otherwise. To be frank, you've already seen this in your own life, for what you and your boyfriend did was wrong in the eyes of God and you have paid a price. The Bible warns, "Do not be deceived: God cannot be mocked. A man reaps what he sows" (Galatians 6:7).
But does this mean God is now punishing you for what you did by somehow turning your son against you? No, I cannot say that. Your son not God is responsible for what he is doing. Yes, you may have influenced him by what you did (or failed to do). But ultimately he is responsible for his decisions.
The most important thing I can tell you, however, is that God loves you, and He wants to forgive your past and change your future. He loves you so much that He was willing to send His only Son into the world to die for you. Invite Christ to come into your life today and He will. Then ask Him to change your son's heart and help him as well as you overcome the past.