Suddenly having strong fetal movements?

I'm 16 weeks 6 days pregnant today with # 2. I posted a question yesterday because up until last night i have not felt a single movement. Not a flutter, a tap, or anything. But last night, i was relaxing on the couch, laying back, and i suddenly started feeling something. It felt like it did with my son when i was 33 weeks. By that i mean i could acctually see the kicks through my belly. Mind you, i am not skinny. I'm very overweight. I'm 5'9 and weigh 187. But i could really see my belly move. Not slightly, but dramatically. Someone told me that my baby is 8 ounces and 4 inches long at this stage. That dosen't seem possible to me. The movements were in the front but on the right side of my belly button, then they were lower on the other side, then above my belly button in the middle. Was this really the baby? I did not feel gassy, and i've never had gas that made my stomach move before. Help? Thank you.