Having a hard time mentally with my pregnancy

Need to vent...I'm really frustrated because I'm so tired all the time. It was hard for me to workout in the first and second trimester because of morning sickness and exhaustion. When I finally did feel better I started doing walks but I had such bad pelvic pain afterward I had to stop. I've tried to workout but everything hurts including my lower back. I feel like I've lost all my muscle and I'm worried I won't have enough stamina for labor. Plus I feel like I look like a giant balloon. 😭😭