“I’m fine” is vague. “I’m nervous about Thursday” is something you can actually work with.

Vague words about how you feel keep the door shut for everyone, including you. Fine is not a description, it is a polite way to end the conversation. Naming the actual thing changes what happens next, because a specific worry has a date, a cause and sometimes a fix. General dread has none of those and cannot be helped by anybody.

Next time somebody asks, try the specific version with one person you trust. Name the thing and the day. Saying it out loud tends to shrink it slightly, and the other person finally has something they can respond to.