Pregnancy and been in contact with someone that has chickenpox help and advice please????

Hi everyone really worried as i am 10+4 days pregnant with twins but i have just found out someone i was with yesterday has now got chicken pox. The spots started coming out yesterday whilst I was with her and she kept cuddling me etc ( i had no reason to think it was chicken pox) now i am worried it is going to harm the babies! What is everyones advice? Should i ring my midwife!?? I have had the pox before bit i have heard people getting shingles which is far worse! Just dont know what to do? Please any advice would be gratefully recieved????