First, Yay for Rescue Remedy! Grew up on the stuff and I still use it for stressful situations.
It is totally fine to use while pregnant. The alcohol used in Bach's RR is brandy and is used solely as a preservative. But the amount of drops you use in a dose is relatively minute so I doubt it's going to really affect your baby. You can use the pastilles (lozenges) or the children's alcohol-free glycerine RR if it makes you fell more comfortable. Potency is not lost in these other vessels.
Also I want to point out that you might be using the "stock" bottle which is intended to be diluted. Did this bottle cost $10 - $15? If yes, it's a stock bottle - the ratio of alcohol preservative to flower essence is extreme. You are NOT going to be hurt by taking drops directly from the stock bottle, BUT flower remedies follow the law that Less is More.
You can get your hands on a glass stopper bottle online or at an herb store. Fill the 2 oz bottle nearly to the neck with clean water (purified if possible). Add 2 - 3 single drops of RR from the stock bottle and 1 - 2 droppers full of preservative (brandy, apple cider vinegar or glycerine if you have it). The alcohol lasts longer but the non-alcoholic preservatives will last for quite a while. Put the top on and give it a couple shakes. Voila'!
And if you love the stuff then diluting in your own dropper bottle will save you tons of money! Think of how many drops you'll get from daughter-ing a 2 oz bottle from 2 or 3 drops from the mother stock bottle. Dude!
I hope this helps!
p.s. I just want to add that I am a certified Natural Therapeutics Specialist. You know, in case Big Brother is reading.