Just want some insight

So I went in today to be seen by my midwife because I was having some cramping that wouldn’t go away at all with back pain and when she checked my cervix it was 1.5 cm dilated and I’ll be 34 weeks Monday . On top of that she can feel that my daughters head is low . On top of that my belly is measuring 3 weeks ahead ..... I’m having an ultrasound done but now I’m nervous because she said we wanna make sure you don’t have a lot of fluid , so I looked it up and now I’m worried about what I read that having to much fluid can do . I was a little chunkier when I got pregnant this time I wasn’t my size 8 like I was with my first so I’m trying to think that may be why , but I’m the other measurements it was always consistent to my weeks .... but overall she had a perfect normal heart beat and is always moving ....