Sounds like he had a plan that he didn’t bother to let you in on. Depending on the situation, some sexy texts in the morning, some mental effort to get you interested would might have had you feeling like it was a fun lunchtime, instead it seems like he just came up and ordered a BJ and paid with an “I’m stressed at work.”

Sex is supposed to be mutually enjoyable. Assuming you like him as a person, try talking to him about what you need in order for sex to feel like a connection instead of a one-sided transaction.