OP YADNBU to be a miffed or put out that he has too work on your birthday and that he should make it up to you.
For all you other 'grown-ups' who think birthdays aren't important here's a quote for you, bear with me its a long one,
"who on earth would genuinely want to wake up on their birthday morning bloomless, cardless, presentless? ...And yet people don't really understand this most fundamental truth, and ignore or 'forget' people's birthdays, becasue they're too lazy to buy a bunch of daffs and stick a stamp on a card. We all want to be loved, and if we can't be loved, with some fanfare, on our birthdays, then really what hope is there?"
India Knight 'The Shops'
Actually in the book its four and a bit pages, its all about how people don't make enough fuss on birthdays.
and to those people who think birthdays are crap after 21 or 14 or whatever please cheer up! Rather than get dpressed about the number, enjoy your day, celebrate FFS!
I grew up on a sheep farm and my birthday falls right in the middle of Lambing time, my parents made the effort but work naturally got in the way, 18th and 21st came and went without any fuss, sob poor neglected me, but it wasn't until I met the love of my life did I really have a truly special birthday and maybe thats the big kid in me enjoying but so what? we should enjoy life not mope around telling people to grow up.