Gut feeling been right?

Y’all idk.. I’m not an insecure person but I do have a little trust issues with my significant other. Anyway, idk today he’s been on his phone and acting sort of weird. I just have a gut feeling he is up to something. It literally hit me like a truck just about an hour ago. We’ve had some issues in our relationship recently and I’ve been totally okay but I can’t explain how this feeling came upon me so quickly. Like instantly I knew. Do I sound crazy? I know everyone is just going to be like “ask him” and I understand that but things have been a little sensitive between us and I’m not sure I’m ready for an argument. He’s very defensive, even when he’s not up to something it’s just how he is. Any thoughts, suggestions, similar stories?