Sorry if the tag is wrong.

EDIT: This is in IL

I have zero experience and little to no knowledge of the legal system.

I also have extreme mental health issues and this is making me really scared and I'm hoping an explanation can help me not be so scared.

Last year I was a witness to someone driving through a BLM protest. And I got it on video. I am now required to show up to the trial in a few months.

Am I testifying? What is required of me? The subpoena had no information other than the court date.

I am scared of retaliation from the family and friends of the acused if I do have to testify.

It's making my anxiety unbearable. I don't know what to expect or do. Other than show up. Where do I sit? Who do I talk to? Do I need a lawyer?