Maybe he's having a crappy day at work. Don't let HIS mood affect you.
The same thing literally just happened to me...I emailed SO thanking him for something he did - I got a curt response back "I'm having a BAD day - I'll talk to you later." So, I texted him back "sorry about your bad day, anything I can do to make it better?". I'm not going to let his problem affect me today, it will only make both of us miserable.
Congratulations on your bonus! Now, go buy yourself something nice with it.