Etiquette - Invitation to bachelorette party,but not wedding!

I agree. I consider the bachelorette party to consist of the bridal party and other good female friends of the bride. You should have gotten an invite to the wedding as well.
 
I've had two instances where co-workers specifically told me that I was going to be invited to their weddings. They even asked for my advice regarding some of the wedding preparations and on a few issues that they were having with some of their bridesmaids or family. In the end, I was never sent a wedding invitation by either person and I just assumed that they probably had to cut back on the number of people attending the reception to save on costs. No apologies or explanation were ever offered and I honestly didn't expect one. However, one of my other co-workers was quite miffed about the whole thing (she was also invited verbally but never received a formal/mailed invitation to the wedding).