Alaaaah jangan worry la, 2.1kg at 35 weeks tu actually okay je! Baby still ada few more weeks to gain weight, so normal lah tu, most babies gain around 200-300g per week from now until delivery, so your little one boleh catch up easily. A few of my mum friends had similar weight at that stage and their babies lahir with healthy weight, so I think you're fine, but just to be extra sure boleh mention to your doctor at the next checkup, okay?