HI there. I just had my 12 week scan. And the babys nuchal fold is normal on one side but 7mm on the other...is this really bad? I'm so worried. Help

Not accurate. The nuchal fold is not measured in this way. It is measured in a very specific way as one measurement not one on each side.
Nuchal fold. Have they scheduled you for a rescan? A scan with a perinatologist. If not, I would ask your provider to have a scan with a perinatologist. By doing so, a higher level ultrasound is done and they will be able to give you better answers.