What action do I take after falling at work?

Last week I passed out at work and in the process of fainting, I fell and hit my lower back (spine) on a sharp counter ledge. I went to the hospital by ambulance and was treated and released the same day. They didn’t take x-rays due to my pregnancy. Now my job’s insurance company is trying to contact me. Do I simply tell them what happened and go about my business? If my injury continues to hurt, what happens in that case? Right now I’m hoping it’s just healing from a bruise. If it causes future problems, what do I do?