I have noticed a swelling or sagging above my pubic area, with varying levels of swelling or sagging. Could this be a hernia? Or any other condition?

Could be. The location you are describing is unusual for a hernia unless you had surgery before and this is incisional hernia. If the bulge is to the side of your pubic bones then the possibility of hernia is much higher. Could be excess skin if you lost weight recntly. Could be a full bladder. The list could be long. See a doctor.