The fact is, weddings cause brides and grooms insane amounts of stress and anxiety. From the moment the guy decides to propose, there's an undue amount of pressure that has to be dealt with. Selecting the perfect place, finding the right ring, and getting the mood for that particular event just right can wreak untold havoc on an otherwise normal and fully functioning mind. Of course, this is nothing compared to the stress and anxiety that comes with actually planning the wedding.
However, the fact is, the most amount of stress and anxiety tends to come at the day of the wedding itself. That's when all the pressure comes down on you and you realize that, at the end of the ceremony, you're going to be bound to one another for “all eternity.” For some, the thought is a welcome one, but for most, there's always going to be that element of uncertainty that causes stress and anxiety to take root once one partner gets to the altar. In some cases, it builds to the point that one half of the pair doesn't want anything to do with the whole affair before the organ even starts playing.
For some, though, all that stress and anxiety pales in comparison to the worries that thinking about the future might bring. Both bride and groom are bound to consider some situations and possibilities of what might happen several decades from the wedding itself, with some of them being perfectly reasonable and others bordering on psychological horror. Is she just after the cash? Will he start looking at other women when she gets old? Will he want kids or not? Will the kids follow her religion or be atheists like him? All of these things tend to pile up and make the stress and anxiety of getting married double, or even triple in some drastic cases.
The fear doesn't even really have to come from the future, as quite a bit of stress and anxiety can come from just the thought of living together. After all, you only really get to know one another when you've lived with each other for extended periods. For those who didn't have a long engagement, this could easily come into play as both parties experience various uncertainties about whether this arrangement is the right move.
However, while all this stress and anxiety is definitely something to be considered, these things are not what one should dwell upon the day of one's wedding. A wedding should be a happy occasion, and one that was prepared for several months ahead of time. Evaluate whether you're just nervous or if you're outright questioning the relationship itself. If you have stress and anxiety the day of the wedding because of the nature of the event, that's fine. In all likelihood, that's a perfectly natural reaction. However, if you're starting to feel nervous because you're not sure you're taking the right step with the right person, then maybe you should have thought about that before proposing, don't you think?