Growth scan at 36 weeks

Okay so I had a growth scan at 33 weeks little peanut was weighing 4lb 7oz had another growth scan at 36 weeks baby was weighing 5lbs 15oz, midwife said baby should be at least 6lbs 3oz but didn’t say I should be worried BUT to keep an eye on movements. Anyone else been here? Of course the second she said she should be 6lb 3ozs my brain went into over drive, I’m not going to lie I’m worried out of mind atm coz she said keep an eye on movements... why, If I don’t have to worry???