Could my symptoms be because of not wearing a maternity belt?

I’m 24 weeks and have a maternity belt shipping to me as we speak. Lately if I’ve been moving around too much I feel a lot of pelvic pressure accompanied by cramping every once and awhile, feeling faint, nausea, with some back pain if I don’t don’t rest enough.

I still look to be about 18 weeks along but the baby is growing just as it should at 24 weeks, but could the added weight be causing all these symptoms? I’ve alway had a flat stomach, this is my first pregnancy, and having abdominal muscle splitting. Any insight, or advice is greatly appreciated, thanks.