Fundal height too large - referred for scan

Hi everyone. I am currently 34 weeks, and my fundal height is measuring 40 weeks. The midwife was a bit worried as i was always right on track before. She referred me for an ultrasound as she suspects I have too much amniotic fluid - she said she was struggling to have a proper feel for the baby because of the fluids!

I’m trying not to worry, but it’s hard not to. What in the world could be going on.. I know for many women, this is not an issue but I also can’t ignore that it can be. I just hope it will all be well. I’m a bit puzzled by all this.