Hello, this is Dr. E. Greetings from New York! I'm so glad you posted your question for me to answer, and I aim to provide you with accurate info
While it is probably a virus showing itself through a rash or even an allergic condition I do recommend you see your obstetrician about this within the next few days. It is safe to take loratadine 10 mg daily if you feel itchy.
I am overseas at the moment and I don't actually have an obstretician back home in Australia (I have a midwife) so do you think I could ask at a chemist? Or should I see a doctor?
You should certainly see a doctor about it as some similar rashes in pregnancy can predict a preterm delivery (ie a rash called pemphigoid gestationis).