Four week check up

Went for my monthly check up. I’ve only gained another two pounds in four weeks. That’s three pounds in eight weeks. I’m eating so I don’t see why I’m not gaining weight. I’m not complaining lol. Just will be easier to shed once baby is here. I’m 19+3 today and go for my gender scan in six days. Eek can’t wait. Heartbeat today was 156. I have two girls and am hoping for a boy. Anyone have a heart rate like that and have a boy? Or is it too high and it’s a girl? Anyone else not gain much weight yet?