Too much weight gain in third tri

I'd say 1kg per week is on the higher side, especially if it's sudden, so it's worth flagging with your gynae or PD just to rule out water retention or anything else going on. Normal third trimester gain is usually around 0.3 to 0.5kg per week, though everyone's different depending on their starting weight and how much they gained before. Since your BP and other signs look good, it's probably nothing serious, but better to check in with your doctor rather than worry yourself, especially since you've noticed the change.