Pelvic pain

Lauren
Hi everyone! So I just found out I am about 4 weeks pregnant with baby #3. All of a sudden I feel that my clothes are already not fitting me and whenever I bend over my uterus or pelvic area has some pressure. I have never experienced this before with my other two. I also have been extremely nauseous. What could this be? Anything I should worry about? Thanks and happy new year!!!