Does it matter which it is?
It depends on how far along you are. Your bump will be uterus. As time passes you will be able to feel it grow upwards from your pubic bone, like a hard semicircle. That is your bump. If you are only a few weeks, it is still well tucked in behind your pubic bone so you have bloating. I just don't think it matters which it is, its all pregnancy. Congrats.