advise

Hey ladies. So I got caught pregnant again really soon after my first born and I had no idea on date of conseption. Anyway after my 12 week scan they game me a due date of 15th of Jan witch puts me at 30.4weeks today. At both scans she has measured on point for the due date been correct but at my first measuring at 28.5 she measured 30cm, 2cm bigger than the 95%. No big deal I know and I wasn't worried now today at 30.4 she's been measured 6 times 2 at 36cm and 4 at 34cm. Witch even on the lowest measurement would put her 4cm above the 95%. Now I know fundal height is not very accurate and is measuring everything but my midwife has already said she has very little waters around her and Iv already been to hospital once with reduced movement and her heart rate was high now today I don't know if I'm been paranoid or if she is moveing less and I'm having really bad period like cramps in my back. Am I just over thinking it all or should I call my midwife unit? I also know that these are 2 separate matters and her size has nothing to do with the cramps and movement