I need help explain to me why

Brittany

Okay when I was three week and 3 days pregnant I started haveing my niplles to be sore and my lower back hurting and I get sick off my vitmains and now my boobs don't hurt my nipples are kinda sore and my lower back hurts in the middle still and it kind hurts in my lower middle of my adomen when my lower back hurts does that mena I'm pregnant