I've lost three people to suicide in my life, each one equally heartbreaking and difficult to understand. My teacher, whom I was very close to and whose son I dated, hung herself in her bedroom. It was completely unexpected and shattered me. A few years later, that same son I dated and remained friends with shot himself. Finally, a friend of our family, who my brothers and sister and I considered our grandpa, shot himself a year after his wife, our granny, died of cancer. He said he was too lonely and just wanted to be with her again. Most recently, this year, my husband's aunt tried to end an addiction to painkillers by ODing. Luckily we found her in time and after some therapy and a stint in rehab, she's much better.
I know how it feels. I remember the questions, the whys, the how could theys, all of it. And although the pain lessens with time, the questions never do go away.
I am so sorry for your loss. I am so sorry for your son's loss. Hold onto him, let the feelings come and allow yourself to grieve. Anger is a normal reaction to a suicide that too many people feel guilty about and try to suppress. Working through it one day at a time, and dealing with that day's emotions is a must. I know for me, just talking to someone who understood, a friend, therapist, whatever, allowed me to get out a lot of that raw pain and anger that I felt so that I could allow myself to grieve and remember the people I loved in a better way.

to you, mama. Hang in there.