Should I be worried? Am I crazy?

Okay so my fiancé is at home and I’m visiting my mother for the weekend, he doesn’t really talk or message well I’m gone which is fine we both need “me time “ but today my last message to him was I was having a bad time here I wanted to come home he said nothing, I figured he went to sleep. Well I woke up at 2 am I usually just go back to sleep well I felt the need to look at my phone this MF is out drinking or something with some person I have never heard of , and the reason I know is his fucking ex messaged like 30 times ( his ex left him for her ex about 5 years ago he never wanted to break up with her he wanted to marry her) she said that she seen him out wanting to know if he got home calling him several times freaking out that she seen him with her old friend so he was out with someone ( she messaged his FB but it’s synced to my phone ) I’m livid with him right now I can’t sleep, this is what I messaged I said you have a lot of explaining to do , then a screenshot for proof In case he denies it , then said I wanted some fucking answers. Im posting because do you think I’m over reacting? This ex has messaged in the past in the span we have been together wanting to start things up again and he’s out with some random presumably chick . Which is fine as long as I don’t hear it from his ex and not him. I feel so sick, I was contemplating just telling him to drop my dog off and then never speaking to him again. I know I’m being crazy I just am worried been together almost 4 years