I wonder if your son would notice if you didn't send him a card. I don't think you're over reacting.
A couple of years ago I was at the hair salon and my hairdresser, a confident and busy lady, was upset because her son hadn't given her a mother's day card. It was the Wednesday after mother's day and he sauntered in and handed her a card. I (yep rudely) said to him "no point now, mothers day was last Sunday". He lived locally so no excuse.
SO no you're not over reacting.... If you're upset and disappointed, you're allowed to have feelings ?
Conflicting high cholesterol and triglycerides advice
34 year old assisted euthanasia