I'm just getting back into biking after years of raising the kids.

I went looking this weekend. I'm 5' tall. The bike store measured my inseam said I should buy a 47 frame. I tried it. I could do it but then I tried a 43 frame and felt happier on it. But it looks so small.
I will be riding with my husband who will (obviously) be on a bigger bike. Does a smaller frame mean I have to work harder to ride the same speed he does?
I'm so confused. I really liked the smaller frame but don't want to be left in the dust.