I'd definitely ask your pregnancy doctor their opinion, if only to get reassurance. Shingles is caused by varicella zoster, the same virus that causes chicken pox. So if you have immunity to chicken pox I wouldn't worry... shingles is not supposed to be contagious unless you don't have immunity to chicken pox, then you'd catch chicken pox and not shingles, and that is only through direct contact with an active shingles rash that is still in the blister phase.
This should help you a bit more:
Congratulations on your pregnancy and don't worry