Hi,
Welcome. I'm glad you're joining us. It's normal to feel tired, sluggish and headachy on Phase 1. The good news is that you're probably over them hump after today. It should start getting better after day 4. Stay hydrated and advil or tylenol should help. Also be sure that you're including your dairy servings and beans. The naturally ocurring carbs in these foods help.
Exercise is up to you. I'm an avid exerciser but was unable to workout during phase 1. I picked right up with my routine when I started phase 2. However, lots of members are able to keep up with their typical routine during phase 1. It's totally up to you and how your body feels.
Good luck and keep us posted on how you're feeling.