I was in the same boat, still am some days. Practice deep breathing when you start to feel overhwelemed so that you can think clearly. Remind yourself that it's perfectly normal to feel out of control, you wont feel like yourself for a while thanks to the hormone tsunami inside.
Really open up to your fiance, just tell him to hold you and listen to whatever spills out, or just cry. He wont judge you, he loves you despite all this. It may seem like he's not being understanding, but remember that he probably has no clue what you're experiencing. I'm sure he does want to help you, even if he doesnt know how. Just having him there to hear you out whole-heartedly can take so much emotional weight off your shoulders.
And moving around a little (like a short walk) followed by a massage or bath might help with those aches and sleeplessness.
Following because I feel/am doing the same thing.