I always have low blood pressure, usually around 100/60 not pregnant. Mine has been shockingly low so far down to 80/50 last week.

I do what others have suggested, take it easy standing, make sure I eat and drink regularly. I do have to be careful when I am out though because I automatically want to drink less (the pee factor!) and I feel quite ill if I do.

As you said it is much better to be on the low side than the high side. But I wish mine were more in the middle