I think there is a lot of stress in planning a wedding and things just kind of snowball out of control. You have all these people involved, usually parents telling you what to do......... I felt like I just had no control over any part of my wedding, all my choices were changed, it really was not my day.
You might feel better if you could talk to someone.Maybe you feel deep down the wedding should not happen but are afraid to stop it. My friend had to take the pre-wedding classes at church and failed the classes with her future husband--then they had to go talk to the clergy for a few weeks and he still refused to marry them. In the end they did get married, but if you are feeling something you have to find out if it is just normal nerves or your instinct to tell you to get out of it.
Good luck.