Why is it every time?

So a little back story... when I was pregnant with my son, I didn’t find out until I was 5 weeks and 3 days. Well, the week before I was super sick, felt like I had the flu and it was horrible. So I thought, maybe I caught something? Well, now I’m pregnant with baby #2 and I’m feeling like that again. My whole body hurts, I’m nauseous, and I’m extremely tired all the time. I’ve had more morning sickness with this baby than I did with my son. I just don’t understand why I feel like I have the flu. Anybody else have this problem?