Already married but wanting to have a big wedding!

Given that you're already married (congrats!), you'll need to find a church willing to do a vow renewal. You're essentially planning a vow renewal. My advice would be to check with your church to see if they'll do it.

You're still legally married. You can't get married twice.

If you're Catholic, there is something called a convalidation ceremony to put the church approval on it.

I'm not sure about other religious denominations, which is why I advised checking with your own church.

Yes, this is absolutely possible! You would just let your church know that you would like to have a vow renewal ceremony! For most churches, a vow renewal will be very similar to a wedding. The biggest differences will be in the wording (since you are already married), and there will be no need for the legal aspects (ie, obtaining and signing a marriage license).

Congrats on coming up on your 5 year anniversary! I'm glad you're going to get the celebration you missed with your friends and family the first time!

Five years later you'd call it an anniversary party or a vow renewal, not a wedding or even a celebration of marriage considering the timeline. I prefer the former personally, since the whole point of vows, including the ones you make in a courthouse, is that they aren't meant to expire. Alternatively, if your church does a convalidation or other religious ceremony for the benefit of already married couples you could invite guests to that and a reception to follow. I agree that you already had your wedding and can't have a redo five years later, but you can have a reception that has all or most of the elements of any wedding reception, ie dress, music, decor, dances, cake, speeches, etc.