Remember this (I learned it here):
"What other people think of me is none of my business"
And then let it go. Stop caring. Focus on yourself. And understand there are at least a handful of people at your workplace who are or have experienced something similar to what you are going through. I am still amazed at how common these life upsets are.
The first time I went to work and sat my boss down to be honest about what was happening to me, I was floored to find out she had also married an alcoholic and her ride was far more wild than mine!
Just tell people the wedding has been postponed due to unforeseen circumstances, then smile and walk away. If anyone presses for an answer, say "illness" and you aren't in a position to discuss it further.
Then proceed on with seeking calm and serenity. This too shall pass.