Hello Sadnamechanger,
I am so sorry to hear about your boy. 10 years is a huge landmark .
I lost my daughter 3 years ago. We marked her first anniversary with lots of friends and ballons and lanterns.
I realised that I could not cope with the pressure of thinking up something every year that could possibly illustrate how much we missed her. I worried that as the memories and pain would never fade, others would naturally move on. This would always be painful, if understandable.
I decided to do something low key that could include as many or few people who wanted to be involved.
I have a small front garden. It was a mess. I spent the day clearing it and weeding, laying gravel and slabs and planting pots and beds. Friends dropped round with plants and I even allowed gnomey type things (fairies and butterflys). At the end of the day I felt uplifted and I had a beautiful garden that was a tribute to my darling girl.
This year I put a gazebo up to shelter me from the rain and worked away all day tidying it all up and replanting. The day is still awful but I know what I am going to do and I am kept busy.
If you feel not eating keeps you close to your son I dont see any problem with that. Its only one day so it wont harm you. I understand your need to feel pain.
I would love to hear more about your boy if you feel able.
Take care.