How do I not yell at my fiancé?

Disclaimer: I’m on my period. I’m in the middle of midterms. I’m stressed as all hell. I’m looking to argue.

But I’m trying to keep my cool.

My fiancé and I are together 3+years. In September, our anniversary came along. He said he had to work but we’d celebrate it on a day he was off. I was like “okay” and he promised to buy tickets to see a play i wanted to see and we’d make a night of it. Well, that play was a limited run and it came and went. Then it was “we’ll make a weekend of it.” But his job rotates which days off he has every month, so we haven’t gotten that weekend yet.

HOWEVER, his friends called him up a few weeks ago and asked him to come down to another city where he lives a weekend in November. We talked about it but like, nothing was ever mentioned. Today I find out he has Friday off of the weekend in November. I was like “cool we can do something” meaning for our anniversary and he hit me with “Well I put in for the weekend with the boys, I don’t know if it’ll get approved though” and I was like “I didn’t know?” And he was like “I just did it now because I’m off Friday.”

Well BOY did I get pissed off because it’s like HELLO?! You can 1) take off an entire weekend for your friends but you can’t take off one day for your anniversary. 2) if you’re going to take off - it’s for your friends? K’

And he knows I’m angry. But I don’t want to fight. How should I approach this?