Feeling of heaviness

Lately I've been feeling heaviness in my lower pelvic area. I do not feel any cramps, have any discharge or any bleeding, and no pain . Have any of you ladies experienced this? Or is this normal? I did not feel this with my first pregnancy. As a result, I feel like I'm starting to waddle already. I don't know if it's cause I'm always tired or dying with this CA heat we got going on. I'm currently 21 weeks. Thanks in advance for your responses.