is nausea a sign of labour?

i woke up this morning feeling fine then suddenly out of nowhere i just feel really nauseous. I had breakfast so i know im not hungry, but not sure if I ate something bad (i only had toast though). I read that nausea can be a sign of labour, but cant always trust what i read on google lol so wondering if anyone else had the same? I have alot of pressure in my belly and have had backache for nearly a week now. im 38+6 weeks