It's just the stress...Unless there are unresolved issues that have been burried?
Or maybe secrets you havnt told that are making it difficult to stay happy?

Take a break from eachither...from talking or seeing each other and have a date night before the wedding to have fun and get in ina good mood for your wedding!

Talk it out ask how he's feeling and explain how your feeling, this will definitely help a little!
Congrats on your wedding and new marriage!