"I was upset for" is a correct and usable phrase in written English. You can use it to indicate that you were feeling a certain emotion for a certain amount of time. For example: "I was upset for days after my friend failed to show up for our appointment."
"But I was upset for another reason too," he admitted.
I was upset for days," says dried fruits seller Zahir Hussain.
I was upset for Caroline, knowing she'd have to be told eventually, and I was bothered about how Sall would take it, after last time.
"I was upset for about 0.2 seconds then realised how cool it was and it made me so hyped," user thestaggie posted on Reddit.
"I was upset for myself, but I was even more upset for the people who had been living there for 20 years or more," she said.
I was upset for all the people who had to go through this, sometimes enforced, sometimes voluntarily, because they were so miserable and life was so difficult".
"I'm upset for myself and the team of clean athletes who ended up out of work.
"I think the tackle was really hard, I'm upset for the Arsenal players, it was a really strong tackle but not to (intentionally) break the leg of the other player.
I'm upset for the [5,000 travelling] fans".
"I worked really hard to turn the last three weeks around and I am upset for my coach who worked really hard to get me in shape".
"I'm upset for one reason, man.
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu