What am I feeling?

mare91

I am 12 weeks 5 days pregnant and from my pelvic bone to about 2 inches from my belly button it is hard, is that my uterus? For the past three weeks I've slowly been growing a belly but now I just look fat so I feel like what I'm feeling is my uterus but I don't know. And also, for about two weeks, when I lay down I feel like bubbles are in my belly? Is that the flutters everyone is talking about?