“Overdoing it” and miscarriage?

Hi ladies. I’m a first time momma to be. 6w1d with twins. I am in New York with my mom for a conference I’m going to tomorrow. We ended up doing a lot of walking today. Our twenty minute walk ended up being almost two hours and I was carrying a 20ish pound bag most of the time. I also didn’t get to eat much during this time and ended up with a headache. I’m finding myself to be an incredibly anxious mom already and I’m absolutely terrified I overdid it today and I’m going to lose one or both of my babies because of it. I know I’m probably overreacting. At least I hope so. Can anyone provide me with some reassurance that it’s probably fine? Or some reality that I might have done some damage. I don’t want to be lied to but I really hope it’s gonna be ok! I have my second ultrasound on Wednesday. It’s gonna be a long five days!