I know you don't want to go to the shower...but your son made a point of inviting you. Are there going to be other men there besides your son and you? If not, you can always send a gift and have something else planned...but I do think your son would be disappointed if you didn't attend. You could go for a little while and then casually leave.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.