measuring 7 weeks too big! (UK)

Hollie • Married, young, SAH Mummy to a beautiful nearly two year old girl and expecting a little man the end of November!
So I'm just wondering if anyone else is experiencing similar or has done before. I'm currently 29 weeks pregnant with my second baby and measuring at nearly 36 weeks! 
At 24 weeks I was measuring 27 weeks and they told me not to worry as it could be a growth spurt but now it's even bigger! My midwife isn't too concerned as I've passed my glucose tests but I'm just worried I'm either going to have a massive baby or end up ballooning even bigger! Anyone else had this? Help me 🙈