First, you both need to sit and have a serious talk about your feelings and future. Second, if he IS having second thoughts, better to find out now rather than later. And third, don't have children until you know for sure where you stand.
Are you sure you are not going overboard on the wedding plans and not paying enough attention to the marriage? Too many women get focused on the big day they forget about the man they are marrying. If you can get away for a weekend without any contact or discussion of the wedding you may find that you can reconnect.
If you can sit down with him and figure it all out it would be better than getting married. If you get married you will suffer always. It has to be mutual. It does not matter if the wedding is 2days away if he wants out don't strap him in. You will be sorry. You have to be strong and try not to let the fact that family & friends will be upset interfere with your diceison to cancel. I have witnessed this and they get divorced eventually.Guys don't fall out of love with a girl because he has wedding jitters there is more to it then that. I know a girl that went to pieces over him wanting to cancel and he actually did get married and wanted to get annulled while on honeymoon.