20 weeks, not a lot of movement

This is our 2nd. We are 20 weeks 1 day now. I started feeling flutters around 13w. Light jabs about 16-17 weeks. It hasn't really increased much. I may feel him a lot one day then it may be several days before I feel him again. With my first it was very frequent from about 18-19 weeks on so it starting to worry me. I was about 50lbs lighter with my first so I wonder if being heavier makes a difference. I have a significant bump but when I do feel him it's still very low. Anyone else not feeling baby very much?!